It's important to know the most critical time in a vegetable's growth to water. Mulching helps reduce the need for extra water.
It's always better to water infrequently and deeply than frequently and shallowly. Frequent light waterings only moisten the top few inches of the soil. The roots will stay where the water is and when dry conditions occur, the plant is more likely to suffer water stress due to the shallow roots. Deep waterings send water down 6 inches to a foot into the soil and the roots will follow. These plants will be more likely to survive a bout of drought.
If the plants aren't indicating it's time to water, the soil will. You can also stick your finger in the soil. If you dig down 3 to 4 inches into the soil and it's still dry, it's time to water.
Evening and early morning are the best times to water because less water is lost to evaporation than with midday irrigation. On disease-prone plants such as roses, water in the morning to encourage the plants' leaves to dry quickly. Also avoid overhead sprinkling.
So, while it's important to keep plants properly watered all season long, there are critical times of the growing season to water. Here's a chart adapted from the book, Vegetable Gardening for Dummies (2009, Wiley), showing the most critical times to water your produce.
Vegetable | Critical Watering Period |
---|---|
Bush bean | When flowering and forming pods |
Broccoli | When forming a head |
Brussels Sprouts | When forming sprouts |
Cabbage | When forming a head |
Carrot | When forming roots |
Cauliflower | When forming a head |
Sweet corn | When silking, tasseling, forming ears |
Cucumber | When flowering and developing fruit |
Eggplant | From flowering to harvest |
Lettuce | When true leaves form |
Melon | During fruit set and early development |
Onion | During bulb enlargement |
Pea | When flowering and during seed enlargement |
Pepper | From flowering until harvest |
Potato | When tubers set and enlarge |
Pumpkin | When fruits form |
Radish | When forming roots |
Spinach | When true leaves form |
Summer squash | When forming buds and flowering |
Swiss chard | When true leaves form |
Tomato | From flowering until harvest |
Turnip | When forming roots |
Not only is the timing of your watering important, how you water makes a difference too. Depending on your area and the season, there may be watering restrictions in place or water may be very expensive. Using efficient watering systems not only will be better for the plant, it can save water and money for you.
Here are some of the common ways to water your garden, with advantages and disadvantages of each. The automated systems described below are best used with a timer that will turn your watering device on and off so you don't have to remember.
Hand water — While it is one of the easiest watering methods, it's sometimes not the most effective or efficient. Hand watering with a hose or watering can is best used on containers and individual plants. You'd be surprised at how long it takes to apply enough water to soak plants' root zone, though. In fact, the most efficient way to hand water is to create a basin or furrow near the individual plant or row and fill it with water. Let it sink in, then move to the next basin. This works particularly well early in the season, when plants are small.
Sprinklers —Above-ground sprinklers are popular for covering large areas, such as lawns. This is probably even easier than hand watering because all you do is set up the overhead sprinkler and let it run for a designated period of time. While the water soaks into the ground well, the down side is you'll be wasting lots of water in the process watering pathways. Also, this type of watering should be done in the morning so the leaves dry before evening. Wet leaves at night are an open invitation to disease. Set up overhead sprinklers so that water falls only on your lawn or garden and not on sidewalks, roads, or buildings. Adjust the water pressure of either type of system to allow water to penetrate the soil without puddling or running off.
Soaker Hoses — A more efficient way to water is to lay soaker hoses around plants and along rows. These low-flow hoses weep water into the soil around plant roots and are less likely to waste water. They work best laid under plastic mulch used around warm season crops, such as tomatoes and melons. Soaker hoses also work best on flat ground to evenly distribute the water.
Soaker hoses concentrate water near roots where the plant needs it the most.
Drip irrigation — Drip irrigation is similar to soaker hoses in that you'll be focusing the placement of water near the plant roots. However, it's even more efficient and wastes even less water. The downside is the cost and maintenance. There are more parts to the drip irrigation system that needs to be checked frequently to open clogs and fix leaks. Plus, drip irrigation is more expensive than any other watering system.
Mulch — Though not a watering system per se, mulch is critical to conserving soil moisture and keeping weeds away. Organic mulches such as straw, pine straw, bark mulch and untreated grass clippings will reduce the amount of watering and weeding you'll have to do during the growing season. Weeds are important to control because they will compete with your plants for water. Plastic mulches conserve moisture too, but work best with a soaker hose or drip irrigation lines running under them to keep the plant roots moist.
Both the frequency and amount of water required will vary with your climate, soil, and plants' needs. Shallow-rooted annual flowers need more frequent, lighter waterings than deep-rooted trees. Heavy clay soil retains water better than sandy soil. The best way to determine how much water to apply, and how frequently to apply it, is to use a shovel. After watering, use the shovel to remove a wedge of soil in the garden or lawn. The soil should be moist to a depth of at least six inches for annual plants, and 12 inches for perennials, shrubs, and trees. Most of the roots plants use to take up water are located in these zones. (Don't forget to replace the wedge of soil.)
A timer is useful to turn on and off your sprinker. You can then begin keeping records of how long it takes to moisten the soil to the desired depth and set the timer accordingly. For example, a weekly two-hour watering might be just right for your perennial bed or lawn, while your annual planting may need just 15 minutes.
To water vegetable and flower gardens containing tall plants that may otherwise block the spray, set sprinklers on a sawhorse, or use a tower-mounted sprinkler.
The other over-watering mistake is good love gone bad. Although there are a very few exceptions to the rule, watering a little bit every day is not what most plants (especially trees) need. Keeping the soil moist with frequent watering is important when starting seeds, establishing transplants, and sometimes in container gardens. Watering daily keeps the roots near the surface of the soil which can result in fried roots in a scorching summer. You are also promoting shallow rooting which then relies on daily water. In contrast, we want the roots of the plants to go deeper into the soil to create more stability and stronger, healthier and more resilient plants. If you have an irrigation system, it is especially important to do periodic checkups. Your system needs to be adjusted seasonally and it's always a good idea to make sure you don't have a midnight geyser.
Limiting the stress of your plants gives them a much better chance at shrugging off insects and diseases. Make sure the care you are giving your plants isn't causing undue stress.
For 25 years, the family-owned Victory Seed Company has provided the highest quality vegetable, herb and flower seeds to families across the country. We are passionate about providing you the best seeds available that give excellent germination, robust plants, and the harvest you want. With a catalog of over a thousand varieties, we have everything, and our prices are the kinds that we'd want to pay. We have hundreds of yesterday's heirloom vegetables, as well as today's award winning hybrid selections. Get to know us by visiting our website and browsing through our online vegetable seed catalog.