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Why You Should Practice Succession Planting for Your Garden

By Spring - Planning & Planting, Summer - Planning & Planting

Denver’s high-plain desert climate presents challenges for gardeners due to its short growing season and frost dates from mid-May to mid-September. However, smart gardeners utilize succession planting to extend their harvests.

This technique involves staggering crop plantings for a continuous yield, maximizing production and offering various benefits for gardeners: 

  • Maximizing Space: With limited growing seasons, succession planting allows gardeners to make the most of available space by efficiently rotating crops and interplanting, a technique that utilizes the space at the base of taller growing crops to plant shorter varieties, thus ensuring that beds are always productive.
  • Continuous Harvest: By staggering plantings, gardeners can enjoy a steady supply of fresh produce throughout the growing season, rather than a single, overwhelming harvest.
  • Soil Health: Succession planting can improve soil health by reducing the risk of nutrient depletion and minimizing soil erosion. Rotating crops also helps to break pest and disease cycles.
  • Season Extension: With careful planning and the use of season-extending techniques such as row covers and cold frames, gardeners can extend the growing season into the cooler months of fall and early spring.
Practical Succession Planting Tips:

Know Your Frost Dates: Familiarize yourself with the average last and first frost dates for your area to determine the optimal planting times for different crops.

Choose Quick-Maturing Varieties: Select varieties of vegetables and herbs that have shorter maturity times, allowing for rapid turnover and successive plantings.

Plan Your Planting Schedule: Create a planting schedule based on the specific requirements and maturity dates of each crop. Consider factors such as soil temperature, sunlight, and water availability.

Stagger Plantings: Plant new crops as soon as previous ones are harvested to ensure a continuous harvest. For example, after harvesting radishes in early summer, replant the space with quick-growing crops like lettuce or spinach.

Interplant Compatible Crops: Take advantage of companion planting by interplanting compatible crops that can thrive together and provide mutual benefits. For instance, plant lettuce between rows of tomatoes to maximize space and reduce competition.

Utilize Succession Planting Beds: Dedicate specific beds or sections of your garden to succession planting, allowing for efficient rotation and management of crops throughout the season.

Monitor Soil Health: Regularly assess soil fertility and health by conducting soil tests and amending as needed with compost, organic matter, and natural fertilizers.

Example Succession Planting Plan:

Consider this example succession planting plan for Denver’s Zone 6a:

  • Early Spring: Plant cool-season crops like peas, lettuce, radish and spinach as soon as soil can be worked.
  • Late Spring: Plant warm-season crops such as tomatoes, peppers, basil and cucumbers after the danger of frost has passed.
  • Early Summer: Replant harvested areas with quick-growing crops like beans and basil; towards the end of June, replant a few summer squash seeds and delta radishes.
  • Late Summer: Sow fall crops such as kale, carrots, and beets for harvest in the cooler months.
  • Early Fall: Extend the season with cold-tolerant crops like kale, arugula, and swiss chard.

Maximizing Small Spaces: Gardening Tips for Balconies

By Spring, Summer, Summer - Gardening in Non-Traditional Spaces

Cities can present unique challenges for gardeners, especially those with limited growing space. However, with the right strategies and techniques, even the smallest outdoor areas and balconies can be transformed into vibrant green spaces bursting with life.

When gardening on a balcony, selecting the right plants is crucial. Opt for compact and dwarf varieties that thrive in containers, such as patio varieties of tomatoes, peppers, herbs like basil and thyme, lettuce, and strawberries. These plants not only fit well in confined spaces but also offer a bountiful harvest throughout the growing season.

Vertical space is often underutilized in balcony gardening but can be a game-changer for maximizing growing area. Consider installing wall-mounted planters, hanging baskets, or trellises to grow vining crops like peas, beans, cucumbers, and small-fruited tomatoes. By training plants to grow upwards, you can take advantage of sunlight exposure and airflow while minimizing the footprint on your balcony.

Container gardening is the cornerstone of balcony gardening. When selecting containers, choose ones with adequate drainage holes to prevent waterlogging, and opt for lightweight, weather-resistant materials like plastic, fiberglass, or resin. Consider using vertical stackable planters or tiered shelving units to create a tiered garden, maximizing space efficiency.

Sunlight is a critical factor in balcony gardening success. Assess your balcony’s sunlight exposure throughout the day and select plants accordingly. Most vegetables and herbs require at least 6-8 hours of direct sunlight daily to thrive. Utilize reflective surfaces like mirrors or light-colored walls to bounce sunlight onto plants, especially in shaded areas.

Proper watering and maintenance are essential for balcony garden success. Monitor soil moisture regularly, as containers can dry out quickly, especially during hot, dry periods. Water plants thoroughly whenever the top inch of soil feels dry to the touch. Consider installing a drip irrigation system or self-watering containers to maintain consistent moisture levels and reduce the frequency of manual watering. Incorporate organic fertilizers and plant-based compost into container soil to provide essential nutrients for healthy plant growth throughout the growing season.

Companion planting and pest control are integral parts of balcony gardening. Use companion planting techniques to maximize space and naturally repel pests. Plant aromatic herbs like basil, rosemary, and mint to deter common garden pests like aphids, mosquitoes, and whiteflies. Introduce beneficial insects like ladybugs and lacewings to your balcony garden to help control pest populations naturally. Consider adding flowers like dwarf zinnias, nasturtiums and marigolds for visual beauty and as an additional source of food for beneficial insects.

Harvesting fresh produce is one of the joys of balcony gardening. Regularly harvest ripe fruits, vegetables, and herbs to encourage continued production and prevent overcrowding in containers. Embrace the satisfaction of growing your own food and savor the fresh flavors of homegrown produce right from your balcony garden.

Gardening in small spaces like balconies requires careful planning, creativity, and a bit of experimentation. By choosing the right plants, utilizing vertical space, optimizing sunlight, practicing proper watering and maintenance, implementing companion planting techniques, and harvesting regularly, you can create a thriving urban oasis that brings joy, beauty, and fresh flavors to your outdoor living space. So roll up your sleeves, grab your gardening gloves, and let’s get growing!

Preserving the Harvest: Three Recipes to Preserve Tomatoes

By Education, Fall, Fall Gardening, Summer

With the bounty of produce coming out of our gardens or at the farmers markets, this is the best time to take advantage of the peak harvest season to preserve summer flavors to brighten up meals during the colder months.  

There are many food preservation techniques like drying, vinegar pickling, fermentation and canning. In this article, we’ll tackle canning techniques focusing on water-bath canning and briefly mentioning pressure canning as a comparison.

Canning is a fairly recent preservation technique in comparison with fermentation, salting or drying/dehydrating. It came as a product of pasteurization ideas to eradicate all possible microorganisms from food and allowing the cans/jars to be shelf stable at room temperature for long periods of time. Unfortunately, the process created some unexpected issues with Botulism caused by the clostridium botulinum, a bacteria that thrives in anaerobic environments (no oxygen) low in acidity. Learn more about it here.

We’ll focus on water bath canning using foods high in acid like fruit jams, salsas, sauces, and pickles. We won’t touch on pressure canning, which is used for foods low in acidity, like vegetables, soups or beans, among others, and which require more careful treatment and much higher temperatures to kill all possible pathogens. 

Guidelines for Water Bath Canning

  • Acidity: Food acidity levels at or below 4.6% are ideal for water bath canning. Therefore, when preparing recipes it is vital to stick to the guidelines until you feel comfortable enough to make changes that won’t compromise the ratios of acidity and, in the case of jams and jellies, sweetness.
  • Recipes: Use recipes from reputable sources only and make sure to follow them to prevent food safety issues. The National Center for Home Food Preservation offers detailed guidelines for different types of foods and different preservation techniques, plus a good base of recipes to get you started. 
  • High altitude adjustments: The processing time of the jars in water bath canning increases with altitude. Most recipes require 10 extra minutes of processing time in a water bath at our Denver altitude. 
  • Equipment: A large pot with an internal rack to keep the jars from up from the base of the pot. Canning tongs, canning funnel, ladle, glass jars and lids.
  • Sterilizing the jars: When canning it is important to sterilize the jars properly by following the recipe’s guidelines. Add jars to boiling water and boil them for 10 minutes. No need to boil the lids and bands, simply add them to hot water just before you need them. Follow  the recommended time for each recipe you find online or in books. Do not skip this step.

Tomatoes
Canning tomatoes is one of the best ways to preserve the summer bounty. The basic guidelines include adding acid directly to the jars before processing, which accounts for low acidity in newer tomato varieties. Do not skip the vinegar as it protects the tomatoes from possible botulism contamination.

Canned Tomatoes
-Tomatoes
-Salt
-Vinegar at 5% acidity or lemon juice
-Pint size glass Jars 

  • Peel and cut the tomatoes into quarters and put them in a large pot. Bring them to a boil over medium-high heat, stirring. Boil for five minutes. 
  • Fill clean canning jars with the hot tomatoes and add 2 tbsp vinegar or 1 tbsp lemon juice and 1 tsp salt per jar. 
  • Process in a boiling water bath for 45 minutes. Take the jars out and let cool at room temperature before storing.

Basic Salsa

You can spice up this basic salsa recipe with your preferred hot peppers, cilantro and any spices you might like.

  • 3 quarts tomatoes, skinned, cored and chopped
  • 2 quarts chili peppers, chopped 
  • 2 ½ cups onions, chopped
  • 1 cup (5%) vinegar
  • 3 tsp salt
  • ½ tsp pepper

Combine all ingredients in a large pot, heat to boiling, and then simmer for 10 minutes, stirring frequently so it doesn’t scorch. 

Fill pint jars with the hot salsa, leaving ⅛-inch headspace. Process pints in a boiling water bath for 20 minutes. (time has been adjusted for altitude to up to 6,000 ft).

Green Tomato Chutney
6 cups finely chopped green tomatoes
1 large, tart apple, peeled, cored, and finely chopped
2 cups light brown sugar
2 cups apple cider vinegar
1 1/2 cups raisins
1 organic lemon, sliced into thin slivers (include peels, discard seeds)
1/4 cup peeled and minced fresh ginger root
1 clove garlic, peeled and minced
1-2 chile peppers, minced
1/2 teaspoon salt
1/4 teaspoon ground allspice
1/4 teaspoon ground coriander seeds
Pinch of ground cloves

– Put all of the ingredients in a large, non-reactive, pot over medium-high heat
– Boil, stirring often, until the green tomatoes and the apples are very soft, the chutney is thick enough when a wooden spoon dragged across the pot bottom leaves a trail that doesn’t fill within a few seconds
– Process in half-pint jars in a boiling water bath for 35 minutes

Summer is a Great Time to Plan Your Fall Garden

By Education, Spring, Summer

With the oppressive heat and fierce summer sun of mid-summer, it might seem too early to begin preparations for your fall garden. However, just like with spring garden planning, getting a head start will help you make the most of the season.

Extend the Growing Season

Fall gardening is an opportunity to extend the growing season and use season extension techniques like hoop houses to continue growing and harvesting until the deep freeze of winter arrives. Soil temperatures inside the hoop house are several degrees warmer than those outside, allowing for slow, but consistent growth.

As the weather cools, the plants accumulate sugars in their leaves to avoid freezing, leading to a ‘sweeter’ overall taste. Hoop houses hold in moisture so with slower crop growth in late fall due to temperature changes and lower light intensities, crops require less supplemental watering. Click here to read more about hoop houses.

Grow Cool-Weather Crops

Cool weather crops, including lettuces, spinach, radishes, peas, and any vegetables in the brassica family such as broccoli, cauliflower, cabbage or kale, are great to sow by seed as a succession to the warm weather crops currently in the garden.

Our Fall Gardening Guide offers a list of crops and range of dates to plant or sow them, soil preparation techniques and more.

You can also read our Five Tips for Fall Gardening to get you started.

Fall is also the ideal time to plant garlic, refresh our gardens with compost, and add a fresh layer of mulch to keep the soil protected as temperatures drop.

If your goal is to allow the garden to rest after you harvest all warm weather crops, then sowing cover crops is a great way to replenish the soil nutrients allowing it to rejuvenate and be ready for the spring. Cover crops act like a blanket, preventing soil loss from wind and water erosion. 

Their roots hold the soil in place and help to improve soil structure. During the process of decomposition, microorganisms and the decomposing cover crops produce sticky substances that glue soil particles together.  This opens up air channels and also increases the water holding capacity of the soil. Click here to learn more about cover crops.

To help you make the most of fall gardening, stop by our annual Fall Plant Sale on Saturday, August 12th, 2023 from 10am – 3pm., where we’ll have cool-weather organic seedlings, cover crop seed, garlic for pre-order (pick up will be in early October), fruiting trees, compost, mulch, and Birdie garden beds.

In addition, we’ll have educational resources and activities to prepare you for a successful season extension.

Quick Guide to Growing Tomatoes in Denver

By Education, Spring, Summer

Tomatoes are one of the most beloved vegetable crops in any garden. Gardeners obsess over which varieties to grow, having to choose from abundant cherry tomatoes, meaty Roma or San Marzano, to less commonly grown heirlooms. 

Cultivating tomatoes in Colorado requires some specific tactics and techniques for success. Gardeners need to adapt their practices to Colorado’s semi-arid climate, dense clay soils, shorter growing season, strong sunlight, and wide-range of weather conditions. Read more in our post about Tips for Successful Gardening in Colorado.

Here are some top tips for success in Colorado:

1- Soil: Amend your soil with 1-inch of compost at the beginning of the season to help loosen the heavy clay creating more air pockets to allow better drainage. Compost also increases microscopic biodiversity, which promotes plant health. 

2- Start seeds indoors: Mid-March is the recommended time-frame to start your tomato seeds indoors, counting that our average last frost is mid-May, this allows 6-8 weeks for the seeds to mature into strong seedings. If you are starting your own seeds indoors make sure to time the process well to allow enough time for the seeds to sprout, grow and become strong, but not too long in advance that the seedlings begin to show stress by becoming leggy, scrawny or yellowing. Read more about Starting Seeds Indoors.

3- Seedlings: If you are purchasing seedlings, make sure to choose short, stocky seedlings without flowers or fruits already developing. Look for healthy plants without yellowing leaves or brown spots that could signal disease or stress. 

4- Temperatures: Tomatoes are warm weather crops and require consistent night temperatures higher than 50F to thrive, which in the Denver Metropolitan Area is around mid-to-late May. Higher temperatures result in warmer soil, which should be above 55F, especially where the plant roots will go. Planting too early can result in stunted growth and propensity to disease because the plant is under stress. Here is more information about Safe Planting Dates.

Pair of hands digging into the dirt, surrounded by some green sprouting plants

Planting Tips
Once overnight temperatures are steadily above 50F, soil temperature is at 55F or above, and you have grown or chosen strong stocky seedlings it’s time to plant. 

  • Dig a hole twice as big as the root-ball of your seedling.
  • Add a handful of Organic Tomato Tone to the soil and mix well.
  • Remove the bottom leaves of the seedling, leaving two to three sets of leaves, and bury the stalk up to two inches below the leaves. The knots around the stalk will develop into roots providing a stronger root-base and a stronger plant. 
  • Water thoroughly.
  • Mulch the area around the base of the plants to prevent water evaporation and soil compaction, and to help keep soil cooler during the heat of the summer. 
  • Leave enough room for large tomato plants to grow; overcrowding your tomato plants can create ideal conditions for disease.

Companion Plants
To give your tomatoes a layer of protection from disease, plant the following around them:

  • Marigolds: Soil nematodes can attack the roots of your tomato plants, however, planting marigolds nearby help deter nematodes.
  • Alliums: Onions or garlic (known as alliums) are great companion plants for tomatoes because their strong smell can help deter aphids.
  • Basil: Besides providing great flavor to tomatoes on a salad, basil planted near the tomato plants can help deter hornworms. 
  • Nasturtiums: These bright flowers are a perfect ‘trap-plant’ for aphids and white flies, attracting them and keeping them away from your tomatoes.
  • Parsley: Similarly to nasturtiums, parsley is a trap-plant for aphids, and once there the hover flies that like parsley will eat the aphids.
  • Plant other flowers or grasses in the garden to attract beneficial insects like ladybugs who are voracious aphids eaters.
  • Read more about Companion Planting.

Caring for Your Tomato Plants
The number one tip we can give you to help you keep your plants healthy is to check them daily and tend to them as they grow. 

  • Prune lower leaves as the plant grows to allow for airflow at the base and reduce the chance for disease like early blight spores, which can jump from the soil onto the leaves.
  • Water the root-base of the plants not the leaves. 
  • Water early in the morning or later in the day when the plants are not under heat stress and can take the water better. 
  • Feed every couple of weeks as the season progresses, lightly working the Tomato Tone around the base of the plant with a small pitch fork. 
  • Remove any plant debris from around the base of the plant to avoid disease or to become a hiding place for damaging bugs. 
  • Refresh the mulch ensuring it’s a good 3-inch deep as the heat of the summer increases.
  • Prune some of the suckers growing between the joints to tell the plant to concentrate on flowers and fruit rather than foliage. 
  • On extremely hot days use a shade cloth to keep the soil cooler and reduce heat stress.

Potential Pests & Diseases

Like any crop, tomatoes can be attacked by a variety of fungus, diseases, or pests. Knowing what to look for can help you address the issue before it’s too late. Here are some of the most common tomato problems:

  • Early blight, gray mold, different viruses can attack the leaves or plant stalks showing black or brown spots. The leaves turn yellow and curl as the plant struggles. Remove all affected leaves (up to a third of plant foliage) and burn them to avoid spreading the disease. 
  • Aphids and spider mites: These tiny bugs can suck the life out of your plants. You can remove them by spraying them directly with water to knock them off the plant. You can also use insecticidal soap to treat large infestations. 
  • Splitting & Blossom-End rot: Both of these are caused by improper watering. Splitting results from overwatering, and blossom-end rot is a result of inconsistent watering that prevents the plants from properly absorbing calcium from the soil. 
  • Greenback and internal whitewalls: This is caused by excess light and heat and not enough potassium in the soil. Cover plants with shade cloth and feed them with Tomato Tone. 
  • Sun scorch: As the name hints, this is caused by too much sun exposure.  
  • Hornworm: Tomato hornworm can eat the leaves of a tomato plant in a matter of days if not removed. 

Read more about Common Garden Diseases and techniques for Integrated Pest Management

Japanese Beetle Management

By Education, Spring, Summer

While Japanese Beetles have been in the Denver area for some time, they seem to have made a much bigger splash the past couple of years, and not in a good way.

Unfortunately, they are here to stay, so we must learn to live with them. Before buying expensive products or embarking on time-consuming journeys to rid the garden of this pest, read these tips so that you can make informed decisions.

Tips for Managing Japanese Beetles in Community Gardens

  • The adult form of the Japanese Beetle is responsible for foliage damage. Hand picking or shaking adult beetles off of plants into soapy water is the best strategy for control during the summer months when adults are actively feeding in gardens. Handpicking is best achieved in the morning when the beetles are more sluggish. 
  • Plants with foliage damage attract more beetles, so handpick regularly. 
  • If you are committed to applying every 3-4 days, you can also use Neem Oil with azadirachtin to control adults. This is an acceptable option for organic gardens. To prevent leaf burn and to avoid hurting honeybees, spray Need Oil in the evening. 
  • Jefferson County Extension recommends making your garden attractive to birds and amphibians that will naturally control adults. Provide a birdbath and a second source of water on the ground to increase predator populations.
  • Traps marketed for Japanese Beetles are not shown to be effective in reducing populations, and in fact the scent emitted by the traps will oftentimes attract more beetles to your garden!
  • Japanese beetles are highly mobile, so just because you are controlling them in your specific garden doesn’t mean they’ll go away. 
  • Eggs and larvae are very susceptible to drying and therefore it is advisable to let lawns go dormant between July and September.
  • In a typical community garden with no turfgrass, control of this pest is focused on the adult form. Adults lay eggs in turfgrass in late summer and emerging larvae feed on turfgrass roots in the fall and spring. Adults are mobile and emerge in early summer. Therefore, biological controls such as milky spore and parasitic nematodes that target the larval stages are not a good use of money or time in a community garden setting where there is typically no turfgrass (but they can be effective options for the home garden and can be found at Arbico Organics).

For more information on Japanese Beetles, read more from CSU Extension: http://extension.colostate.edu/topic-areas/insects/japanese-beetle-5-601

Common Diseases of Garden Vegetables

By Education, Spring, Summer

Fungal diseases can take an entire crop if not quickly identified and treated.

The damage can include wilting, scabs, moldy coatings, rusts, blotches and rotted tissue, among other symptoms.

Learning to identify what is attacking your plants can help you stay ahead of the damage and prevent it from spreading, as well as find ways to avoid it in the future.

Crop Disease Symptoms
Alliums (Garlic, Leek, Onion)
Downy Mildew Early symptoms are sunken spots on leaves; later, a purplish mold develops over spots
Pink Rot Roots turn pinkish or red, eventually rot; plant is stunted with wilted tops
Smut Black spots on leaves and between the sections of the bulbs; young plants may have twisted leaves; common in northern regions
Asparagus
Asparagus Rust Reddish-yellow spots on stems, branches; gradually entire plant yellows, weakens, and eventually dies
Fusarium Wilt Wilted, stunted spears with brownish surface color
Bean, Lima
Bacterial Spot Reddish-brown lesions on stem leaves, and pods; young diseased pods may fall from plant
Downy Mildew Plants are mottled with white, fuzzy fungus strands on them.
Bean, Snap
Anthracnose Dark red, sunken spots on leaves and stems; pinkish-red spots on pods; seeds are often black
Bacterial Blight Large brown blotches on leaves, possibly bordered with yellow or red; water-soaked spots on pods; seed may be discolored
Mosaic Leaves crinkled with mottled areas; pods may be rough misshapen
Rust Many small reddish-orange to brown spore masses on leaves and possibly stem; leaves rapidly yellow dry up, and drop
Beet Leaf Spot Small, round, tan to brown spots on leaves and stems; later leaves turn yellow and drop
Brassicas (Broccoli, Brussels Sprouts, Cabbage, Cauliflower, Turnip) Black Rot Leaves yellow, veins become black; plant becomes stunted and heads of cabbage, cauliflower, or Brussels sprouts are one-sided or nonexistent; stem cross section shows a brown, woody ring
Carrot
Leaf Blight Yellow to whitish spots on leaves; girdling of roots; water-soaked spots or lesions on roots
Root-Knot Nematode Small galls on lateral rootlets; pimple-sized swellings on main root; plants may be yellow and stunted
Celery
Blights (Early and Late) Greenish or water-soaked spots on leaves; sunken lesions possible on stalks; growth may be visible in wet weather
Fusarium Wilt (Celery Yellows) Reddish tissue on stalks and leaves; yellowing of foliage
Pink Rot Water-soaked spots on stalks; bitter-tasting, rotted stems; damping-off may occur in an infected seedbed
Corn
Bacterial Wilt Pale, streaked leaves; yellow, sticky substance exudes from a cut stem
Corn Smut Large galls develop on stalk, ears, and roots; later, grayish galls blacken and release spores; ripened spores appear oily or powdery
Cucurbits (Cucumber, Pumpkin, Squash)
Anthracnose Small, dark spots on leaves; eventually spots grow together and entire leaf is destroyed; frutis may blacken and drop; problem develops in warm, moist conditions
Bacterial Wilt Leaves wilt quickly, possibly while still green; white, sticky material might be seen when a stem is cut
Downy Mildew Yellow to purplish spots start on leaves, gradually cover entire plant
Mosaic Leaves of cucumber and squash develop rough, mottled surface; cucumber fruit may be entirely white; plant may be stunted and yellow in several places
Powdery Mildew Round, white spots on undersides of leaves; eventually entire leaf is covered with powder; fruits ripen prematurely and have poor flavor and texture
Scab Dark spots on fruit of cucumber and pumpkin; leaves may have water spots and stems may have shallow lesions; sap oozes from fruits, then greenish mold develops
Eggplant
Fruit Rot Brownish spots on leaves; damage is particularly bad during wet weather when fruit may develop small, tannish cankers which later rot
Verticillium Wilt Yellowing of foliage and gradual defoliation; plants may become stunted
Pea
Ascochyta Blight Leaves shrivel and die; roots and lower stems may blacken and rot; disease overwinters on plant debris
Bacterial Blight Brownish or yellow blotches form on leaves and pods; stems may turn purplish; leaves eventually yellow
Powdery Mildew Stems, leaves, and pods dusted with white powdery mold; black specks appear later in the season; plants are stunted and vines shriveled
Root Rot Yellowed, gangly plants with rotting roots and lower stems; plant may die before pods form
Pepper
Anthracnose Dark, round spots on fruit; entire pepper may rot or dry up; serious problem particularly in southern or central regions
Bacterial Spot In dry areas, leaves develop yellowish spots with darker margins; older leaves eventually drop
Potato
Blackleg In warm, moist climates, plants become stunted and leaves yellow and roll; stem base develops brown, rotted areas on the inside; inside of tubers shows darkened blotches and a soft rot that worsens during storage
Early Blight Spots develop in rings on leaves; eventually leaves may die; tubers develop puckered skin and shallow rough lesions; mold may result
Mosaic Mottled, crinkled foliage; brown specks appear on tubers, and plants may droop and die prematurely
Rhizoctonia Dark brown cankers appear on young sprouts; mature stalks may become brown; tubers are covered with hard, black “scurfs”; tubers may also be roughened in a cross-patched pattern
Verticillium Wilt Late in season, older leaves yellow; affected vines die prematurely; stem tissue discolors from base; tubers may be pinkish
Spinach (also Swiss Chard)
Blight Yellowish, curled leaves; stunted leaves and plants
Downy Mildew In moist areas, leaves develop yellow spots with fuzzy, purplish growth beneath
Sweet Potato
Black Rot Small, round, brown spots on potato tubers; stem may also show decay
Soft Rot Soft, watery rot on stored tubers
Stem Rot Young infected plants may die after trans-planting; survivors develop bright yellow leaves, and later stems rot; harvest is of poor quality
Tomato
Anthracnose Fruits develop small, round, water-soaked spots; later, fruits darken and rot
Blights (Early and Late) Irregular, water-soaked spots may develop on leaves; plant becomes partly defoliated; seedlings may girdle; stem end of fruit becomes grayish-green; blossoms or young fruits may drop
Fusarium Wilt Leaves yellow and droop; cross section of stem shows brownish liquid within; fruit usually decays and drops
Mosaic Mottled leaves; young leaves are bunched or puckered; plants are stunted; yield is reduced; in some types of mosaic, fruit is also mottled

Dealing with Flea Beetles

By Education, Grow a Garden, Spring, Summer

Flea beetles are tiny, black, and shiny, and will leave lacy patterns in plant leaves, from cabbages to tomatoes.

‘Jungle Judy’ Elliott, DUG’s Community Education Cultivator,  gave us some tips for treating plants affected by flea beetles:

  • Pull any badly affected plants out.
  • Lightly scratch the soil surface, also known as cultivating the soil, around the plant to expose the pests to birds.
  • Spray the tops and bottoms of affected leaves, and the soil around the plant, with soapy water every three days or so.
  • You can also use organic insecticidal soap.
  • Alternatively, you could spray with a hot pepper mixture. Combine half an onion, 2-3 cloves of garlic, and a hot pepper (seeds and all) in a blender with water. You can also add strong smelling herbs like oregano and sage if you have them on hand. Blend, let sit overnight, and then strain with cheese cloth or a coffee filter, then dilute with water by 50% before spraying plants.
  • To strengthen plants, you can spray with kelp.
  • For preventing infestations, companion plant your brassicas and tomatoes with strong smelling plants like garlic and onions.

Have more questions about organic pest management? Join our upcoming Pests & Diseases workshop. Register here.

Companion Planting Guide

By Education, Grow a Garden, Spring, Summer

Companion planting is the practice of growing different crops near one another to enhance crop production, repel damaging pests, improve soil health, and promote biodiversity.

Three Sisters Garden
Utilizing companion planting also helps maximize your garden space, by pairing different types of plants, like tall plants to provide shade to smaller plants, vining plants like squashes to help with weed suppression, and flowering plants to attract beneficial insects. A great example of companion plantings is ancestral The Three Sisters Garden or Milpa, which includes corn, beans and squash. The corn provides a natural support trellis and shelter for beans, peas and other climbing crops. In return, these legumes provide nitrogen to the soil for the corn and squash plants. Squash and pumpkin leaves shade the smaller bean and pea plants that need sun protection and provide weed suppression.

Here is a list of the most crops and their preferred companions:

Vegetable Plant with Do not plant with
Beans Potatoes, carrots, cucumbers, cauliflower, cabbage,

summer savory, most other vegetables and herbs

Onions, garlic,

gladiolus

Beans, Bush Potatoes, cucumbers, corn, celery, summer savory,

sunflowers, strawberries

Onions
Beans, Pole Corn, summer savory Onions, beets,

kohlrabi, sunflower

Beets Onions, kohlrabi Pole beans
Cabbage Family (cabbage, cauliflower, kale,

kohlrabi, broccoli)

Aromatic plants, potatoes, celery, dill, chamomile, sage, peppermint, rosemary, beets, onions, thyme, lavender Strawberries, tomatoes, pole beans
Carrots Peas, leaf lettuce, chives, onions, leek, rosemary,

sage, tomatoes

Dill
Celery Leek, tomatoes, bush beans, cucumbers, pumpkin, squash
Corn Potatoes, peas, beans, cucumbers, squash, pumpkin
Cucumbers Beans, corn, peas, radishes, sunflowers Potatoes, aromatic

herbs

Eggplant Beans
Leek Onions, celery, carrots
Lettuce Carrots and radishes (lettuce, carrots, and radishes

make strong team grown together), strawberries, cucumbers

Onion/Garlic Beets, strawberries, tomato, lettuce, summer savory,

chamomile, beans (protects against ants)

Peas
Parsley Tomatoes, asparagus
Peas Carrots, turnips, radishes, cucumbers, corn, beans,

most vegetables, herbs (adds Nitrogen to soil)

Onions, garlic,

gladiolus, potatoes

Potato Beans, corn, cabbage, horseradish (should be

planted at corners of patch), marigold, eggplant (as a lure for Colorado potato beetle)

Pumpkins, squash,

cucumber, sunflower, tomato, raspberries

Pumpkin Corn Potatoes
Radish Peas, nasturtium, lettuce, cucumbers
Soybeans Grows with anything; helps everything
Spinach Strawberries
Squash Nasturtium, corn
Sunflower Cucumbers Potatoes
Strawberry Bush Beans
Tomatoes Chives, onion, parsley, asparagus, marigold, nasturtiums, carrots, limas Kohlrabi, potatoes, fennel, cabbage
Turnip Peas

Here is a list of the most commonly planted herbs and their preferred companions

Herbs Companions and Effects
Basil Companion to tomatoes; dislikes rue intensely; improves growth and flavor;

repels mosquitoes and flies.

Beebalm Companions to tomatoes; improves growth and flavor.
Borage Companion to tomatoes, squash, and strawberries; deters tomato worm;

improves flavor and growth.

Caraway Plant here and there; loosens soil.
Catnip Plant in borders; deters flea beetles.
Chamomile Companion to cabbages and onions; improves growth and flavor.
Chervil Radishes; improves growth and flavor.
Chives Companion to carrots; improves growth and flavor; plant around base of fruit

trees to discourage insects climbing trunks.

Dill Dislikes carrots; improves growth and health of cabbage.
Fennel Plant away from the garden; most plants dislike it.
Garlic Plant near roses and raspberries; deters Japanese beetle; improves growth and

health; plant liberally throughout the garden to deter pests.

Horseradish Plant at corners of the potato patch to deter potato bugs.
Hyssop Companion to cabbage and grapes; deters cabbage moth; keep away from

radishes.

Lamb’s Quarters This edible weed should be allowed to grow in moderate amounts in the garden, especially in the corn.
Lemon Balm Sprinkle throughout the garden.
Marigolds The workhorse of the past deterrents; plant throughout garden especially with

tomatoes; it discourages Mexican bean beetles, nematodes, and other insects.

Mint Companion to cabbage and tomatoes; improves health and flavor; deters white cabbage moth.
Marjoram Plant here and there in the garden; improves flavor.
Nasturtium Companion to tomatoes and cucumbers.
Petunia Protects beans; beneficial throughout the garden.
Purslane This edible weed makes good ground cover in the corn.
Pigweed One of the best weeds for pumping nutrients from the subsoil, it is especially

beneficial to potatoes, onions, and corn; keep weeds thinned.

Rosemary Companion to cabbage, bean, carrots, and sage; deters cabbage moth, bean beetles, and carrot fly.
Rue Keep it far away from sweet basil; plant near roses and raspberries; deters

Japanese beetle.

Sage Plant with rosemary, cabbage, carrots, beans, and peas; keep away from cucumbers; deters cabbage moth and carrot fly.
Summer Savory Plant with beans and onions, improves growth and flavor; deters bean beetles.
Tansy Plant under fruit trees; companion to roses and raspberries; deters flying insects,

Japanese beetles, stipend cucumber beetles, squash bugs, and ants.

Tarragon Good throughout the garden.
Thyme Plant here and there in the garden; it deters cabbage worms.
Yarrow Plant along borders, paths, near aromatic herbs; enhances essential oil

production.

Adapted from Organic Gardening and Farming, February 1972, pp. 32-33, 54, and The Encyclopedia of Organic Gardening, Rodale Press, Inc., 1978, pp. 233-235.

Gardeners Can Save Water and Grow a Bountiful Garden, Too

By All Seasons, Education, Grow a Garden, Summer

If you have been paying attention to the news, you’ve seen a lot of coverage on the Colorado River Basin and its dwindling water supplies the “bathtub” rings of Lake Mead; the controversy of which states can reduce their water usage and when.

Walking through our verdant community and home gardens, it may seem like water scarcity is someone else’s problem. But climate change, a growing population and annual weather events (or the lack of them) are squeezing nearly everyone’s water supplies. Even our largest and most stable local water providers in Colorado are prioritizing water conservation policies and programs. Aurora Water, which serves the city’s population of more than 386,000 and provides some water to surrounding communities, is experiencing concerningly low reservoir levels and has declared Drought Stage 1 with watering restrictions going into effect on May 1.

While conserving water during a drought is critical, we all need to do our part to conserve water every year. The more of a buffer we can create between our water demand and our total supply, the more resiliency we have to handle the unexpected. 

There is a lot of water to be saved outdoors, even in our vegetable gardens. With the right tools and methods, your veggie patch will use less water than a traditional Kentucky bluegrass lawn.

What are these amazing conservation tools and methods?

  1. Healthy soil
  2. Mulch 
  3. Watering low and slow
  4. Choosing water-wise plants
A person with gloved hands is scooping dirt out of a tipped wheelbarrow

Healthy Soil
Soil that is healthy for growing vegetables and saving water is soil that is rich in organic material, airy and contains moisture. The natural soils of the Denver metro area are generally lean and either very clayey or very sandy, which is not a healthy environment for veggies. Amending your soil is therefore necessary every year. We recommend organic amendments, meaning materials derived from living matter.

Organic amendments such as compost (purchased or homemade), worm castings, composted manure and coco coir will not only add nutrients, but will increase the water holding capacity of sandy soils and improve the tilth of clay soils. Those elements help water slowly move through the ground and reach your plant’s roots.

In the spring, cover your entire garden with two to three inches of your chosen amendment (or a mix) and till it in. After harvest in the fall, you can cover your beds with a layer of leaves. The base of the layer will decompose over the winter, and then you can till it all in with an additional amendment the following spring.

Mulch is Magic
Organic mulch makes the magic happen. It benefits your vegetables in so many ways:

  1. Retains moisture in the soil
  2. Prevents erosion
  3. Cools the surface of the soil
  4. Inhibits the growth of weeds
  5. Reduces compaction as you weed or harvest
  6. Prevents soil surface crusting so that water doesn’t run off
  7. Keeps plants clean
  8. Creates a tidy look

Select an organic mulch that will decompose quickly, such as straw, grass clippings, dried leaves, non-glossy newspaper or a combination of those. Start off with a layer three inches thick and replenish throughout the season as needed.

Watering can watering garden bed

Watering Efficiently
There is a lot to know about applying water efficiently in the vegetable garden. Vegetable gardens in our region generally require about one inch of water per week, but the efficient gardener pays attention to the weather and adjusts accordingly. Your plants’ watering needs will change as they mature. For seeds and small seedlings, water shallowly and keep soil evenly moist which may mean watering daily if temperatures warrant it. When seedlings are at least four inches tall and have several mature leaves, you can reduce watering to about every other day to encourage deep root growth. 

Don’t use your eyes to check if your plants need water—use your fingers. Seeing some wilting during a hot day is okay. To know if your plants really need water, check the moisture level two inches below the soil surface with your fingers. If the soil is obviously moist, dark and cool, no need to water.

Avoid overhead watering. It’s tempting to rely on your pop-up sprinklers, but that can trap humidity that encourages the growth of powdery mildew and other diseases.  

The most efficient type of irrigation for a garden is in-line drip. You can add a drip zone for your vegetable garden onto your current sprinkler system (it must have its own zone). Update your controller settings each month, as your veggies need a lot less water in April than in July.

Alternatively, you can connect a regular hose to drip tubing or soaker hoses on top of your mulched bed and run it. You can then run your hose manually. Do not bury these hoses because of concerns that soil may get into your water line. We don’t recommend hose bib timers, as they can break and waste hundreds of gallons or worse.

Hand watering works best for small areas or containers. Always use a nozzle on your hose to slow down the volume and flow rate and water as close to the ground as possible. Do your hand watering in the coolest and least windy parts of the day. In the summer, that means before 9 a.m. or after 7 p.m.

Go Water-wise
Many of us love to plant vibrant annuals like marigolds near our vegetable gardens to attract those awesome pollinators! Generally, annuals require more water than water-wise or native perennial flowers. So switch it up by planting a water-wise and/or native perennial border to accomplish the same purpose. After the perennials are established, they’ll need little to no water. Make sure to mulch them with a three-inch layer of mulch like bark or wood chips. They’ll use less water while providing habitat for the bees and other insects that pollinate our vegetable plants.

This article was written by Diana Denwood, Senior Water Conservation Specialist for Aurora Water

For more information on Aurora Water Conservation Plan click here