Mulching for Water Conservation

Make roses more drought resistant by mulching well, but keep mulch clear of the woody base of each plant.

This year you’ll hear a lot of suggestions for helping your landscape make it through drought. Some are truly actionable while others may prove problematic. For example, many sources recommend relying on drip irrigation. This may be ideal for your veggie and flower gardens, but it can prove troublesome for trees and shrubs with vast root systems that don’t always respond well to poorly placed pinpoint watering.

Aside from smart irrigation, the second most effective way to help your beds and borders survive is to apply mulch. Mulching for water conservation is important. Mulch acts a lot like a sun hat on a very hot day; sun hats protect the head from direct sun exposure, keeping the body cooler and the face shaded. Mulch also reduces evaporation of water below its surface. There are many mulch options, the best being composed of partially decomposed organic material that is easily spread over the soil’s surface around plants.

Why mulch during drought?

There are three key reasons to apply mulch to beds before or during drought:

1. Mulch protects the soil surface from direct solar exposure, so the soil remains much cooler in the heat of the day.
2. Mulch acts as a moisture barrier keeping water from evaporating from the soil surface.
3. Mulch stops weeds from succeeding, which means more available soil moisture for your garden plants.

What materials make good mulches?

Black Gold Compost is a super mulch for the vegetable garden.
Black Gold Garden Compost is a super mulch for the vegetable garden.

Mulching during drought requires a thick layer of organic matter spread out over the surface of the soil. Fine bark mulch, pine straw, leaf mulch, and compost are all good organic mulching products. Knowledgeable landscapers utilize a 2-inch thick layer of mulch that’s thick enough to provide benefits but not so thick that rain or irrigation water cannot permeate the layer from above. Some forms of mulch, such as coarse bark mulch, do not break down easily, so they remain in place for a long time.

When rich, semi-decomposed soil amendments are used as mulch, they offer the additional benefit of adding quality organic matter, which increases soil fertility. Black Gold Garden Compost Blend feeds microbes in the soil while protecting plants from potential dehydration and heat when water is limited. When rains finally do return, this rich mulch can be turned under to add more benefits while the coarse bark mulches are best left on top.

How do you spread mulch?

You may be surprised to discover how much material is required for adequate mulching. Go cheap with a thin layer under 2-inches thick, and your garden will be riddled with weeds and the soil’s surface may crack from dehydration. Landscapers begin applying mulch by placing evenly spaced bags (or wheelbarrow loads) of mulching material over an entire garden area. Next, they use a shovel to stab the bags to break them open, so the contents are easily emptied when one end of the bag is picked up.( Be sure to collect and recycle the empty plastic bags.)

Remove grass in a ring around your young trees in lawns, then apply mulch to create free drainage to the tree roo
Remove grass in a ring around your young lawn trees, then apply an even 2-inch layer of mulch. Be sure not to mound mulch along the trunk!

The mulch is then spread to the correct thickness with a hard rake, being sure not to layer any over plant crowns or trees/shrub trunks. Mulch allowed to accumulate against a trunk or stem can cause crown rot. Avoid it by keeping several inches clear around the base of stems/trunks. When mulching slopes, allow more clearance on the uphill side to manage and reduce runoff and downhill accumulation. In windy areas, it helps to water and compact the mulch, if it’s fine like Black Gold Garden Compost, so it won’t blow away.

Mulching will always be the most effective way to reduce water demands without sacrificing plant health. For this year of weather extremes, don’t expect miracles because just keeping plants alive may be enough. Then when the rains return in abundance, your garden plants will spring up from that semi-dormant state more vigorous than ever.

Spread mulches in and around your herbs and perennials to preserve soil moisture.

Begin Saving On A Rainy Day By Installing Rain Barrels

Rain Barrel
A well-placed rain barrel offers a practical solution for water catchment. Photo courtesy of Schultz Communications.

It is a small project, but installing rain barrels onto your downspouts will capture free non-potable water that could make a big difference in your garden.

How much water? Depending on the size of your roof and your catchment system, a rainfall of only 1-inch should fill a typical 55-gallon rain barrel to overflowing. That is a lot of water that you won’t have to pay for later.

What about eliminating mosquitoes potentially attracted to the standing water? Use Mosquito Dunks® made with B.t.i., bacillus thuringiensis israelensis, a naturally occurring biological control that is safe for birds and pets.

~Photos are courtesy of Schultz Communications




Mosquito Dunks
The natural bacterium contained in Mosquito Dunks kills mosquito larvae without harming birds, fish, pets or humans. Photo courtesy of Schultz Communications.

Re-Hydrating Potted Plants

Pot in Bowl - Maureen Gilmer
Watering potted plants is easy, but getting the whole root ball wet is hard. When you let the root ball dry out it shrinks away from the inner walls of the pot. If you pour on water, it goes straight down this gap and out the drain hole. The best way to rehydrate a plant in peat based potting soils wets the entire root ball, encouraging roots to travel into the center.

You can do it on the kitchen counter by filling a shallow container with a few inches of lukewarm water. Then set the potted plant right into the water. Let it sit until the surface of the potting soil is visibly wet. It may take at least an hour, then remove it to drain in the sink before returning to its place. Do this whenever a plant (indoor or out) has become overly dry to give the peat time to rehydrate completely.

Pots in Box - Maureen Gilmer

Switch to Drip Irrigation

Black Gold
A new bed with drip irrigation installed.

Written by Nan Sterman

With water shortages from California to South Carolina, Arizona to New York City, even rainy Pennsylvania, what’s a garden lover to do? Adapt. We need to choose plants that survive on little more than rainfall. We need to improve our soils so they absorb and hold water. And we need to make our irrigation systems more efficient. Our task is to grow great gardens using as little water possible, applied as efficiently as possible.

Improving soils can be done with the addition of worm castings (Black Gold Worm Castings) to promote fungi, bacteria, and other beneficial microbes in the soil. Compost and mulch (Black Gold Garden Compost, Black Gold Soil Conditioner or Black Gold All Purpose Potting Soil) improve soil texture and provide the organic matter that feeds the microbes.

In terms of irrigation, it is time to replace fashioned overhead sprinklers with drip irrigation. With drip, nearly 100% of the water that goes into the garden goes into the soil where plant roots are. Overhead sprinklers, on the other hand, waste half of the water they put out. Some evaporates into the air, some is lost to over spray. Much of it simply ends up running off into the gutter. With so much waste, your out of pocket cost is twice what it should be. And, keep in mind that all that water running off your property carries fertilizers, pesticides, herbicides, and other toxic materials into our lakes, rivers, and oceans. The cost of this pollution is enormous.

Drip just makes sense. It delivers water where plants need it at their roots, in the ground. In fact, drip is so efficient that when water agencies set watering restrictions, gardens watered by drip irrigation are excluded.

How drip works

Drip releases water drip by drip. Where overhead irrigation delivers water on the scale of gallons per minute, drip releases water on the scale of gallons per hour. Even in gardens with heavy clay soils, water absorbs into the ground rather than running off into the gutter.

There are different types of drip technologies, many of which I’ve tested in my own garden. The hands-down winner is in-line drip irrigation. In-line drip (also called “dripperline”) comes from different manufacturers, but all basically operate the same way. In-line drip irrigation consists of a flexible plastic tube, roughly a half-inch diameter, with emitters installed permanently inside the tube. When you look at the tube, you see a hole every six or twelve or eighteen inches along its length. Run your finger along the tube over the hole and you can feel the thickness of the emitter.

In-line drip is different from laser drip, which is simply a tube with holes drilled in it. In-line emitter tubing releases a set amount of water from each emitter along its entire length. Emitter technology prevents roots from creeping in.

Some brands have check valves so that when the line turns off, water stays inside rather than running out and flooding the lowest point. In-line drip fits together with simple, push-in elbows, t’s, and other fittings. In most garden beds, lines are laid out in a grid, then covered over with a layer of mulch to help hold water in the soil. Because there are so few parts and pieces, these systems are very low maintenance. There are no tiny tubes to blow apart, no heads to twist off, break off, or get stepped on. Just remember to push lines aside before you dig in a bed.

There is some cost involved in the initial installation, but with drip irrigation, worm castings, and a nice thick layer of mulch, you’ll soon recover your costs in saved water and healthier plants.