Gardening Resources

Water Conservation in Community Gardens

Gardening in Colorado mandates the conscious use of effective water conservation techniques. We believe community gardens should be models of efficient water use, especially in seasons of drought. Additionally, use of water conservation techniques has several other benefits including reduced water costs and weed proliferation. If the following techniques are applied, plants will respond by growing quickly and by producing an abundant harvest. We’ve also outlined a set of water restrictions required of all community gardeners in response to the ongoing drought. Regardless of the duration of the drought, however, DUG advocates that gardeners adopt these techniques as standard gardening practice.

  • Water plants in the cool of the day, especially during the evening
    Watering first thing in the morning or an hour or so before sunset allows plant roots to utilize moisture more efficiently. Late day watering allows the water to percolate into the soil for 12 hours or more before the sun and wind magnify the effects of evaporation and transpiration from soil and foliage. Mid-day watering is a poor use of gardening time and an extremely inefficient way of watering into thirsty soils. Since plants do a significant amount of their growing at night, it makes sense to provide moisture prior to this critical period.
  • Water the roots and soil, not the leaves
    Although some plants, such as the broccoli family and lettuces, don’t mind overhead watering and moist leaves, most vegetables prefer watering at soil level. Tomatoes, peas, and members of the squash and melon families can suffer from disease problems that proliferate on wet foliage.
  • Cultivate the soil before watering
    Hoe the soil around plants at least once a week. This serves a dual purpose, cutting off germinating weeds that compete for moisture, and also opening up our heavy clay soil so that water can more easily penetrate to deeper levels. Watering should be done after cultivation, while the soil is loose and airy.
  • Compost throughout the season
    Compost should be applied at the beginning of the gardening season, digging two inches of compost into the top four to six inches of soil, as well as several other times during the summer and fall. Spread a shovel of compost around vegetables, flowers, and herbs, lightly cultivating the soil to incorporate the organic material. Since compost has the ability to hold up to 100% of its weight in water, this allows soils to hold and release moisture and organic nutrients slowly. Having compost-enriched soils is one of the best water conservation techniques available to gardeners.
  • Space plants so that mature leaves shade the soil surface
    Soil that is in shade, even in conditions of drought, is more capable of retaining moisture and reducing evaporation. The mini-climate that is produced by plants that are spaced so that mature leaves almost touch provides a shading and cooling effect of the soil surface below. You can extend the growing season of cool season plants, such as lettuce, by growing in the shade of taller plants such as pole beans. Their leaves provide a living mulch to help cool the roots of surrounding plants and to retain moisture.
  • Mulch any uncovered soil areas
    Mulch conserves water, moderates soil temperature, helps to prevent erosion, and slowly enriches the soil with humus as it decays. Pesticide-free grass clippings that have dried out for a few days, fall leaves or clean straw, are all excellent sources of mulch. Exposed soil areas that are not being used for growing, quickly become weedy and unsightly and are spaces where wasteful evaporation occurs. Mulch warm season crops, such as tomatoes and peppers after the soil warms. Mulch cool season crops, such as lettuce, peas and broccoli several weeks after they have been transplanted or after they have been growing for about a month after germination.
  • Check soil for needed moisture
    Most vegetables need about an inch of water per week for adequate growth. Poke a stick or your finger an inch to two inches below the soil surface to see if water is needed. Soils that are exposed to the sun (with no mulch), and are deficient in organic matter, will be significantly less efficient at retaining moisture and nutrient supplies than those that are shaded and compost enriched.
  • Wilting leaves don’t always signal a call for water
    Large leaved plants, such as those in the pumpkin/squash family, normally droop during the heat of the day. Plants are just minimizing the water loss (due to transpiration), and watering them at this time will increase water loss rather than lessen it.  It also weakens the plants by promoting shallow rooting structure.
  • Utilize efficient watering tools
    Using a hand-held watering wand with a shutoff nozzle allows you to water underneath leaves, close to the soil surface. This also breaks the force of the spray and lessens effects of soil compaction and erosion. Water with a low volume spray, as this lets water percolate deeply into the soil. Clay soils absorb water slowly. Watering for a short period of time, allowing the water to infiltrate the top layer, and then remoistening the area is a more efficient watering technique rather than short, intense watering. As an alternative to hand watering we suggest the use of black soaker hose snaked through your garden at the base of your plants.
  • Harvest frequently
    Harvest crops while plants are actively producing and healthy.  Overgrown, insect and/or disease-laden plants should be removed and the area replanted to another type of plant or seeded with a cover crop. When the plant is taking more out of the soil than it returns, it is time to concentrate on soil improvement.

Composting Basics

What is composting?
Composting is: The purposeful decomposition of organic materials, to create humus.

Why compost?
Compost added to soil can help anything grow. Compost also:

  • Reduces water consumption (can lower water bill by about 20%)
  • Acts as a natural pesticide
  • Improves soil condition
  • Diverts contents from landfills
  • Reduces methane gas

Building the compost pile:

  • Gather carbon and nitrogen materials first. The ratio should be 2/3 carbon, 1/3 nitrogen by volume. Ideally, a pile should be 3’x3’x3′.
  • Carbon (browns) include: newspaper, cardboard (not shiny), paper towel and toilet paper rolls, wool, cotton, vacuum cleaner sweepings, dryer lint, coffee filters, stalks from perennial plants, end of season annual plants, branches, dry leaves, egg cartons made from paper, paper (not shiny).
  • Nitrogen (greens) include: fruit or vegetable peels and cores (no need to remove seeds), coffee grounds, all non-meat food scraps, pet or human hair, manure from herbivores (plant-eaters only please), seasonal thinnings from the vegetable or flower garden.
  • Never put bones, dairy, meat, fat, or any plants treated with pesticide in a compost pile.
  • Scrape back about 1″ of topsoil. Add a 4-6″ layer of chopped, mixed carbon. Then add a 2-3″ layer of chopped nitrogen. Add one handful of garden soil. Mix carbon and nitrogen layers with a garden fork and water until pile feels as wet as a wrung-out sponge. Continue adding layers of carbon and nitrogen material, watering and mixing as described above, until the pile reaches at least 3′ in height, and cover pile with a sheet of black plastic, held down with rocks.
  • Commercially made compost bins are available, and act as a container for the pile. They require all the same components, conditions and attention as an open pile.

Maintain the pile:

  • The compost pile should be turned once a week, rotating materials from top to bottom. This is a guideline, not a strict rule.
  • Add water if the pile doesn’t feel like a wrung-out sponge.
  • Add chopped food scraps to the middle of the pile, covering them with some of the carbon material.
  • Assess the pile each week; tweak levels of ingredients, water and air.

Troubleshooting:

  • Smelly- The pile is too wet or has too much in the way of nitrogenous materials. Pull it apart for a while or add carbon items like cardboard/paper, dry leaves or mowed straw.
  • Not decomposting- The pile is not wet enough. Add water. Activators such as fish emulsion and seaweed can also be added.
  • Attracting animals- Bury food scraps and turn pile more often

Maturing the compost:
The compost is finished when:

  • It looks like a dark brown potting soil
  • The contents are not recognizable
  • Pile is reduced to about half its original size.

Let it sit untouched, under plastic for two months before using. If your goal is to continue composting all of your kitchen and yard scraps, you will now begin composting in another location.

How to use compost:
When ready to use, dig a couple hands full of mature compost into the top 4” of soil for plants. Compost can also be applied lightly as a top-dressing several times a season around all actively growing plants. Compost is extremely rich in nutrients and should only compose 25% of potting soil.

Notes:
Remember that composting happens naturally, and we are just aiding the process to speed it up. Don’t stress about getting it exactly right. There are only five ingredients in compost- carbon, nitrogen, water, air and time. Sort of like making a cake, if you use the right ingredients you can mess it up a little and still get a cake. You will learn as you go what works best for your pile. Have fun, know you’re doing the earth a great favor, and get ready for a beautiful, healthy garden!

This resource was prepared by Stacy Feeney, Denver Urban Gardens Master Composter 

Vermicomposting Basics

Vermicomposting, nature’s ultimate recycling system, utilizes a specific type of worm to process large quantities of organic materials. After digesting the edible components, worms produce nutrient-rich remains in the form of worm castings, or vermicompost, an extremely rich form of compost.

Why vermicompost?

  • Worm compost (castings) can be added to indoor plants as well as outdoor plants as a rich form of plant food.
  • Vermicomposting reduces the amount of garbage produced and sent to the landfill, because food scraps, dry leaves, and newspaper are used in their bedding.
  • Redworms (Eisenia foetida), the type of worm used in worm bins, reproduce rapidly and can be shared with others for starting their own worm bins.
  • Worm bins, when maintained properly, produce little or no odor.
  • Worm bins are small, compact and perfect for apartment dwellers.
  • It is easy to maintain a worm bin than a compost pile, which needs to be turned weekly.
  • Worm bins are an easy way to introduce children to composting and caring for the earth.
  • Worm bins can be kept indoors during the winter and relocated outdoors during frost-free months, thus extending the composting season to year-round.
  • Worms are great pets – they are quiet and you don’t have to walk them!

Making a worm bin:

  • A worm bin can be started in a 10-gallon Rubbermaid container in a dark color. Around the sides, the bottom, and the top of the Rubbermaid container, drill small holes about 3” apart. This will allow airflow in the bin. You may provide a tray or additional lid for the bottom, to capture any draining liquids.
  • Collect dried leaves for the bedding.
  • Tear up newspaper into small squares to mix with the leaves. Avoid any shiny pages (usually used in advertisement inserts) since the ink used in their processing could be toxic to the worms. Fill the container almost to the top, using equal amounts by volume of leaves and newspaper for the bedding.
  • Cardboard that is free of wax, herbicides, pesticides and bleach may also be used for bedding. Avoid using paperboard, the material typically used for cracker, cereal, and shoe boxes, as it contains waxes and glues that can harm the worms.
  • Add warm water to the leaves and newspaper until the mixture feels like a wrung out sponge. A worm’s body is more than 90% water so it is important to keep the bin moist.
  • Add well-chopped, non-meat food to the bedding, making sure to bury the food about an inch below the surface of the bedding. See below for more information on feeding your worms.
  • After moist bedding and food are in place, it’s time to introduce red wigglers (also known as manure worms or brandling worms to their new home). Avoid using the larger earthworms known as ‘night crawlers’ as they are unsuitable for indoor composting. Worms should be carefully placed on top of the bedding. They will then migrate downwards to escape the light. Finish by covering the bedding and worms with several damp pieces of newspaper to maintain an even level of moisture in the bin.
  • Place the worm bin on a tray or extra lid to collect any moisture that drains through the holes on the bottom on the bin.
  • Collect leaves and newspaper to renew the bedding as it decomposes.

Maintaining the worm bin:

  • Worms should be fed once a week. Aerate the bedding each week, feed in a different part of box each time, and make sure worms have eaten most of food before feeding again. Do not overfeed the worms.  If you do, you will attract flies and the bin will start to smell. If the worm bin is too wet, add newspaper and leaves. If too dry, add a little bit of water at a time.
  • Worms eat their weight in organic matter each day. One pound of redworms will process one pound of organic matter daily.
  • Keep the worm bin in a cool, dark, dry place as worms do not like light.

Food that is suitable to add to a worm bin includes:

  • Vegetable and fruit trimmings as well as the peel
  • Stale bread
  • Used tea bags and tea leaves
  • Toilet paper or paper towel tubes (make sure there is no glue on the roll)
  • Newspapers cut into small pieces
  • Vacuum cleaner dust
  • Coffee grounds and filters
  • Crushed eggshells (helps with worm digestion)
  • Cardboard, plain and corrugated (no shiny cardboard or paperboard)
  • Avocados (worms love avocados)
  • Dried leaves

 Food unsuitable for worm bins include:

  • Citrus fruits
  • Meat, including chicken or fish
  • Bones
  • Glossy paper (like magazines and shiny newspaper inserts)
  • Salt
  • Spicy vegetables (onions, hot peppers)
  • Sawdust
  • Dairy products
  • Garden weeds
  • Potato peels and sweet potato peels (could sprout in the worm bin)
  • Fruit seeds
  • Junk food (chips, candy, etc.)

Harvesting the castings:

Vermicompost is usually produced in two to three months. Worm castings look and feel like dark, moist, forest-scented soil. When the worm bin is entirely filled with dark, moist compost, it is time to remove the vermicompost from the bin and set up new bedding for the worms to start over. Remove the worms either by hand or sift out into another container.

This resource was prepared by Yvonne Greenbaum and Carol Murphy, Denver Urban Gardens Master Composters.