Growing food in a drought presents a number of challenges, difficult decisions, and actions to implement them. A critical issue is being aware of a limiting water budget—restrictions imposed by a city or county agency or a household well.
Planning a water budget is similar to other budget planning. In drought conditions, it means determining what water savings can be made to allow for a food garden. Possibilities are briefer showers; saving indoor water for outdoor use; turning off the tap unless absolutely necessary; flushing less; running the washer with full loads, using water-saving toilets and faucets; and installing a gray water system to irrigate landscape ornamentals.
Next comes determining how far the savings will stretch between household needs, garden bed size, and crop choices; then comes planting only what your family likes to eat and how much they can consume. Once you’ve made these determinations, put water-wise practices in place. Briefly, these practices include:
- Compost, compost, compost! Add organic matter to the soil. In sandy soil, organic matter allows the soil to hold more water. In heavy soil, organic matter opens up pore spaces to improve aeration and water movement, allowing roots to go deeper and access water at lower depths. Compost increases soil nutrition and better yields. With ample compost, no additional fertilizers are needed.
Compost and rice straw mulch in raised bed. Arborist mulch in path. Photo by Stephanie Wrightson. - Mulch, mulch, mulch!Mulch keeps soil cool, conserves moisture, and reduces weeds. Use 3-4 in. on top of the soil. The larger the material size, the deeper layer you need to provide. Choose from straw, fallen leaves, hulls, shredded bark, grass clippings and newspaper. It is not advisable to use plastic sheeting as mulch because it deprives the soil of much-needed oxygen. Keep mulch 2 in. away from the base of the plant to avoid the possibility of rot. When hand watering, pull back mulch so that water goes directly into the soil. And do not cover a seed bed with mulch until the seedlings are 3-4 in. tall. [Note: wood mulch, dried leaves, etc. would not be appropriate near the house from a fire-wise standpoint. Use 2 in. of well-decomposed compost on top of the soil to serve as mulch.]
- Use a drip system. Use a drip irrigation system for the most efficient application of limited water. Group plants that have the same moisture needs together on the same valve and irrigate only as long as it takes to moisten the active root zone. For most crops, the active root zone is 6-12 in., but deep-rooted perennial crops require moisture at least 1 ft. deep. Water in the morning or in the cool hours of the evening and only as much as needed so soil stays evenly moist, not wet. That is best accomplished by portioning out weekly water needs on a daily or every-other-day basis. The drip system efficiently delivers nutrients to the root zone where your crops need them. Monitor and adjust the drip system as needed.During an average Sonoma County summer, water loss is about 1 in. per square foot a week due to evaporation and plant transpiration (ET). During extremely hot periods, it may be more. Water loss due to ET is what needs to be returned to the garden.
Drip system in Stephanie's vegetable garden. Photo by Stephanie Wrightson - Be selective.
- Learn about moisture needs of individual crops and grow only the amount and types of foods the family will consume. For example, plant two beds of vegetables instead of six; plant four tomatoes instead of ten.
- To get the most out of the water you apply, grow high yielding vegetables like beans, chard, mustard, eggplants, peppers, tomatoes, squash, quinoa, and amaranth.
- Consider which crops need the most water and when:
- Some beans and sweet corn need considerable water to produce a good crop. Beans need water most when they are blooming and setting fruit.
- Corn needs water most during tasseling, silking and ear development. Yield is directly related to quantities of water and nitrogen and spacing.
- Peas need water most during pod filling.
- Other vegetables, such as cucumbers and squash, and fruits, such as melons, need water most during flowering and fruiting.
- Tomatoes, peppers and eggplant need water most during flowering and fruiting. (Note that after tomatoes set, they can do very well with reduced water, or even no water after they start to ripen).
- Avoid crops that need consistent heavy moisture unless a particular variety has been bred to need less water. Most brassicas (broccoli, cabbage, Brussels sprouts, kohlrabi, cauliflower and radishes), lettuce and other greens, beets, carrots and other root crops, celeriac, celery, leeks and onions perform best with regular water.
- Generally, cool season crops are not drought resistant and growing them during the heat of the summer requires lots of extra water.
- After deciding what to grow, choose varieties labeled with the terms “drought-resistant” or “drought-tolerant” in seed catalogs or on plant labels (note that “heat-tolerant” refers to above ground air temperature and is not the same as drought-resistant or drought-tolerant). Selecting varieties that are described as “widely-adapted” in addition to drought-resistant and drought-tolerant also is helpful.
 Red and gold beets in shade of tomatoes. Photo by Stephanie Wrightson |
Additional Information
- Year-Round Gardening in Sonoma County
- Food Gardening with Less Water
- Composting
- Mulch
- Food Gardening Resources
October 2022