As we brace ourselves for this week of 95+ degree heat and even more hot summer days ahead, it’s important to know how to water your garden effectively and efficiently. Fruit and vegetables cost a lot of water for a plant to produce, so watering adequately will promote healthy plants and an abundant harvest. Insufficient watering can cause problems in the garden. In addition to making your plants wilt, inadequate watering actually stresses plants, which can lead to unhealthy and unproductive plants that are more susceptible to pests. Below are five best practices to follow when watering your vegetable garden.
1. Know your plants
If you watch your plants, they will let you know when they need water. They wilt. Colors become dull. Furthermore, different plants have different water requirements. For example in a standard vegetable garden, onions do not need as much water as carrots, and carrots don’t need as much water as tomatoes, cucumbers or beans. Potatoes are very sensitive to not enough water, but peppers like it hot and dry.
The age of the plant also matters. The more mature and bigger the plant, the less water it requires compared to young and small plants. Young plants are tender and have small root systems whereas a mature plant will have a bigger root system to cover more area below ground. Always remember to water immediately after transplanting a young plant!
2. Know your soil
The ability of soil to store water is dependent on the soil texture, which is the ratio of sand, silt, clay and organic matter in a soil. According to Washington State University Extension, a 5% increase in organic material quadruples the soil’s water holding capacity. Organic matter not only holds and stores water but also insulates the soil against heating and cooling. One of the easiest ways to increase a soil’s water holding capacity is to incorporate more organic matter in the form of compost.
Mulch (i.e., straw, grass clippings, woodchips, leaves, composted manure or compost) will also add organic matter to the soil as it decomposes while helping to smother weeds as well. Place a 1 to 2 inch layer of mulch on the soil surface around your plants or place mulch between plant rows. Start by using small amounts at a time so you don’t cause mold or fungus problems.
3. Deep watering
Watering deeply generally means watering a plant so that the water soaks down to at least 8 inches below the soil surface. This encourages a plant’s roots to grow long and deep. The saying goes that one deep watering is much better than lightly, more frequent waterings. This is because brief waterings may not penetrate the soil and reach the roots. It also encourages shallow roots, which dry out easier and are more susceptible to stress.
Soak your garden once a week to a depth of 6-12 inches and don’t water again until the top few inches begin to dry out. If you’re not sure when you need to water again, use the finger test. For the finger test, stick your index finger in the soil, up to the knuckle. If the soil feels moist, there is no need to water. If it’s dry, it’s time to water again.
4. Timing is everything
What time of day you water and how frequently you water is very important. The cool of the evening is the best time to soak or drip irrigate a garden, because this gives the soil and plants all night to absorb the water. Early morning is an ideal time for sprinklers. The leaves of a plant can still absorb the water in the cool of the morning but dry out during the day which minimizes any leaf molds or fungus.
Also, avoid watering when it’s windy. Since windy conditions increase evaporation, it is inefficient for plants to absorb water. In fact, windy conditions even cause evaporation directly from the leaves of the plant as well. If possible, give your plants extra water before or after a warm windy day.
5. Keep water on site
If you have a hard pan developing on the surface of your soil, it won’t absorb water well and instead run off and pool up in your garden path instead. Try loosening the top inch of soil around your plants with your fingers, a hand trowel or to help the soil absorb the water.
Also, try watering slowly or in several stages a couple minutes apart so that the soil has time to absorb the water. Build up small mounds several inches high with your hands around the edges of your garden bed or around individual plants. This will act like a moat or dam and help keep water where you want it–at the base of your plants.
Keep in mind that every garden and every garden plot is different, so we recommend trying a couple of these things to find what works best for your garden. If you have questions specific to your site, ask your community garden leadership committee or garden mentors. They are always willing to help!
Good luck and stay cool!