Everyone knows how to water plants, right? Well, actually, wrong. I was reminded of this during a recent community landscaping project, where we planted hostas, daylilies, grasses and more for a local nonprofit. It was all good, until watering time. Those plants we’d all labored over were given the lightest baptism of water, and the volunteers prepared to head out.
Fortunately, some of the experience gardeners in the group realized the problem, got out the watering gear and gave everything a good soak. Another volunteer came back a few days later to give them another soaking.
Watering is critical for healthy plants and an attractive, productive garden. It’s also an immensely time-consuming task and it can cost you money if you lose plants because of improper watering. Be sure you’re doing it right.
Baby new plants
Seeds should be watered lightly every day or two to keep the top of the soil moist. Small seedlings, such as tomatoes, and established annuals and perennials (those grown in cell-packs or pots of one gallon or less) should be watered every day or two. Water deeply and well — applying around a gallon of water per plant with each watering.
With newly planted trees and shrubs, water them for about a half-hour or so with the slowest trickle of the hose.
All new plantings need a good soak not only to give the new plant moisture but also to settle the soil so there are not air pockets that can dry out roots.
Water Less Often, Deeply
The golden rule of watering gardens is to water deeply and well rather than shallow and often. Frequent, light waterings result in the roots staying where the moisture is — the surface — and growing shallow. Watering deeper and less often encourages roots to grow down deeper where the soil stays moister longer.
What about rain?
Most plants in our Iowa landscapes do best with approximately 1 inch of water a week. If you don’t have one already, install a rain gauge so you can monitor it.
If the rain falls short of that, you may need to do additional watering, apply a half inch or whatever of water from the hose or sprinkler. How to know how much water you’ve applied? Set out an old cake pan, tuna can, or any other shallow, flat container where the sprinkler will hit it and collect water so you can see how much has been applied.
Keep an eye on your plants
Plants that need water look less shiny or glossy. If they start to wilt, the plant is becoming stressed and needs immediate watering. Avoid wilting. A wilted plant instantly becomes more susceptible to insect, disease, and other problems.
Pay attention to the soil, too. Wiggle your finger or a stick into the soil to check. Another trick: Look at your impatiens. These thirsty plants are usually the first to show signs of dryness.
Water Early in the Day
Watering right before sunrise is ideal, so set up a timer. You’ll avoid the heat of the day and prevent evaporation. Early watering also allows plants to dry off well before nightfall, when fungal diseases take root.
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If you can’t do the pre-sunrise thing, no worries. Just be sure to water by midmorning, when the day’s heat sets in.
Water Soil, Not Leaves
As much as reasonably possible, avoid spraying plant foliage during watering since it makes them more prone to disease. Of course, sometimes you’ll need to use a sprinkler and getting the leaves and flowers wet will be unavoidable. But when using a hose or watering can, water just the soil.
Even better: Consider a drip-emitter system, micro-sprinklers, or black soaker hoses. All of these types of hoses slowly apply water without waste exactly where you want it. Black soaker hoses work best with row crops or plantings of shrubs that are placed altogether, rather than assorted annuals and perennials. Also, they’re unsightly, so they need to be covered with soil or mulch. Another problem is that if you bury them, they always seem to get sliced with a spade.
Veronica Lorson Fowler is co-publisher of The Iowa Gardener website at theiowagardener.com.