This year is shaping up to be a poor water year. Future storms are uncertain so consider what you can do to make the best of limited water this summer. While it’s a good idea, I’m not talking about water-wise landscaping. Instead let’s focus on having a productive garden even if water is limited.
Increase Organic Matter
Whatever your soil type, it will benefit from increased organic matter. It is the great stabilizer of the soil world. In a coarse soil it increases water-holding capacity and in a fine soil it increases infiltration rate. Organic matter can be pictured as a sponge, soaking up water and nutrients when available and slowly releasing them over time. The best time to apply organic matter (manure, leaves, grass clippings, compost, etc.) is in the fall. A light to moderate (1-3 inches) compost applied and worked into the soil in spring should be safe for planting.
Mulch is great for reducing water loss to evaporation and weeds. A mulch is a layer of material covering the soil surface around plants. It keeps the soil around garden plants covered, reducing evaporation, and limiting weeds. Every weed growing uses water that a garden plant can’t. Laying down a mulch of unsprayed grass clippings, straw, newspaper, or compost around your vegetable plants will keep soil cool and moist and can reduce your irrigation needs by 50 percent. Plastic mulch is also valuable. It is simply a plastic film, usually black, laid over the soil surface. Holes are made in the plastic for plants to be placed. This warms the soil (ideal for our short season climate) yet it is impervious to water, so it retards evaporation. A caveat is that you must use some sort of drip or micro-irrigation system with plastic mulch.
Utilize Drip or Micro-irrigation
For what it’s worth, my opinion is that everyone should take a serious look at drip/micro-irrigation. Recently there has been an explosion of hose, fitting, and emitter options that make these systems economical and easy to install. They water slowly and deeply at the base of plants. A soak every four to five days may be sufficient for mature plants, especially if mulch is used. Water is applied only where it is needed, efficiency is maximized, and weeds are greatly reduced. Sprinklers are typically rated at 50% irrigation efficiency whereas drip and micro-irrigation are around 90% efficient, meaning nearly all the water applied is used by the plants. We are hosting a class on May 26, on designing and installing these systems.
Limit Nitrogen Fertilizer
Nitrogen is a vital plant nutrient. For a robust, productive garden it typically needs to be added each year. However, too much can be counterproductive. Nitrogen encourages green growth. Some garden plants need it more than others. I tend to use too much for my tomatoes. I get lots of vines that are slow to produce fruit. The more nitrogen you apply, the more water your plants will need to support their green growth. It’s a balancing act but something to be aware of. Colorado has a good nitrogen guide for specific vegetables (Search: Colorado Vegetable Gardening Nitrogen Recommendations).