Watering During the Dry Days to Come

Pat Ferguson
Adams County Master Gardener

Thinking back to May and June with all the rain we had, now it’s a stretch to think of hot, dry days! But they’re coming, so let’s get prepared! When we talk about watering during the hot, dry months, there are many variables to consider. Some of these are:

The soil: Good soil is the most important beginning to gardening! Is your garden soil mostly clay? If so, you will see that water just runs off instead of soaking in. Add soil amendments (compost or other organic amendments like peat). Perhaps your soil is a sandy-type? In this case you will notice that water does not run off, it does go right into the soil. The problem is that it drains out immediately. You will need to add soil amendments like peat moss, manures, compost, or organic matter. If you are working with straight topsoil, be sure to add amendments like perlite or vermiculite, peat moss, humus, or composted cow manure because topsoil is so dense.

The location: Plants under the eaves of your house or in southern, southwestern or western exposures need to be watered more frequently since they get very little water from precipitation and the reflected heat from the walls leads to increased water stress and heat stress. Be careful what you plant next to rocks or a blacktop or pebble driveway since these surfaces are so hot and retain heat.

The wind: Wind, breeze, moving air - it sounds so pleasant, so relaxing, so cool, inviting, so plant-friendly. How could this innocent little wind possibly have any effect on gardening? HA! Last week, an innocent little wind toppled my very large potted hibiscus, swirled away eighty-six blooms of my new and prized yellow New Guinea impatiens, and I’m still picking up little pieces of the angel-wing begonia that looked so nice on my porch. Wind can dry out the soil and dry out your plants very quickly. Unfortunately, most people just look at their plants to see if they have begun to wilt, judging that if they are wilted they need water. Alas, if a plant has begun to wilt then it has already suffered water stress. In a weakened condition, that plant cannot cope with the normal problems of insects, diseases, etc.

The mulch: Those plants located under eaves or very near the walls of your house certainly benefit from a layer of mulch about 2 inches thick. The mulch helps to keep the roots of your plants at a more even temperature, it helps the soil underneath it to retain moisture and nutrients and mulch will also help keep weeds down. When mulching, remember that, besides water, one of the basic requirements of any plants’ roots is oxygen. If you pile up mulch around the base of plants, shrubs, or trees, the roots have little chance of getting the oxygen they need. Pull the mulch out from the base of your plants and trees and make a little circle of the mulch away from the trunks or stems. You’ll end up with a kind of well which will hold more of the moisture in the area of the roots.

The water: Plants need deep, thorough soakings. It is truly far better to water less frequently but for a longer period of time. If we are fortunate enough to get one inch of rain in a week, that is generally considered sufficient to a well-established garden. Notice the qualification – "well-established"! If your garden is new or your annuals are planted "high", then you are going to have to supplement that one inch of water. It’s better to water in the early morning if you possibly can. Night waterings can create ideal conditions for disease development including fungus.

The method: Deep soaking is the goal. The most ideal and water-conserving method is one that provides a slow, steady trickle of water. Soaker hoses or irrigation systems set on a very slow setting fill this need. By watering in this manner you achieve several important objectives; the water you use does not run off the soil but instead reaches the roots below making your plant stronger in the long run; the water that reaches the roots helps the plant to conserve the nutrients it needs to grow and develop; and by conserving the plant’s nutrients, it becomes stronger over time and more drought-tolerant.

Over-watering: One final word on the subject of watering is the caution not to overdo the thing! Believe it or not, over-watering is as detrimental to your plant’s health as under watering! It encourages stunted plants, root rot and fungal diseases. Over-watering also tends to leach nutrients and lime out of the soil causing poor growth and acidity. Finally, over-watering can wash chemicals, fertilizers, weed killers and plant nutrients off your property and into streams, rivers, ponds, and lakes. Such a situation can contaminate groundwater and eventually, drinking water. There is a balance to watering that is easily achieved, it just takes a little practice and knowing your garden conditions.

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