Last month's hot weather sparks 'Mayday!' for mulch


June 08, 1991|By MIKE KLINGAMAN

Gardeners are like sailors. We all heed wise old proverbs.

Gardeners memorize their favorite sayings, such as: Plant the potatoes on St. Patrick's Day for a bumper crop. Or: Sow the carrots when the first maple leaves appear.

I do, I do. I follow this hand-me-down garden lore and, generally, I am rewarded for it at harvest time.

However, there is one adage I have crossed off my list. It reads: Never apply mulch until the tomato plants blossom.

All right, who's the wise guy responsible for that quip? The bozo nearly burned up my garden beds this year.

The hottest May on record in the area shot temperatures past 90 degrees for seven straight days. The effect of the searing heat on the garden was predictable. The spinach bolted immediately. The lettuce hesitated, then followed suit. Forget the radishes; I suspect they will taste like Fireballs this year.

The peonies blossomed in record time. I can't say I noticed the bearded irises at all, probably because they grow in the front yard and I was stuck out back. The vegetable garden needed my constant attention.

All I did in May was water, water, water.

I watered the beds because I had not mulched them.

I never mulch until the tomatoes bloom. In June. That's when I buy several truckloads of shredded bark from a local lumber mill and spread it 2 inches thick on the gardens.

Next year, I'll be better prepared.

Mulch is a blanket that protects plants from blistering summer heat and drought. It also checks weed growth, prevents erosion and, in some cases, feeds the soil. In the hands of an able gardener, mulch has more uses than a Swiss army knife.

However, mulching one's garden too soon in spring prevents the soil from warming naturally and promotes disease among young seedlings.

By June, my garden is like an oven and the plants are ready to be tucked in for the summer. But before I spread the bark, I remember another old proverb: Mulch is like a quilt. Cover the bed, but never your head.

In other words, leave several inches of space between plants and mulch.

There are dozens of different mulches from which gardeners can choose, depending on their availability. Seaweed, peanut shells and spent hops make great mulches, but not everyone lives near the ocean, the circus or a brewery.

Inexpensive organic materials, such as grass clippings and compost, break down and add nutrients to the soil. (Add lawn clippings in thin layers to the ground or the grass will form a thick, smelly clump.)

Shredded leaves and pine needles both make nice mulches. So do ground corn cobs, cocoa shells and licorice root, if you can find them.

There are reports of people using everything from cat litter (unused) to seashells to cover their gardens. Note: seashells leach lime into the soil, so keep them away from acid-loving plants like azaleas and rhododendrons.

Newsprint is a cheap, albeit ugly form of mulch. Spread it several sheets thick and avoid using pages

with colored ink, which contain lead.

Both peat moss and sawdust "cake up" when dry and thus make lousy mulches. They are better used as soil conditioners.

Though increasingly expensive, oat straw is a good mulch for the vegetable garden. Hay provides the soil with more nitrogen than straw does. But hay also contains more weed seeds.

Inorganic mulches are gaining popularity. Many gardeners lay a sheet of thin, black plastic on the garden bed and drop their plants through holes made by bulb planters.

Black plastic may raise the soil temperature by 3 degrees or more, and can be used in early spring without fear of damaging young plants.

Some gardeners who use black plastic cover it with a layer of straw in late spring to keep early-season crops like broccoli and cabbage from overheating.

As for shredded bark (my choice), remember that it can rob the garden of nitrogen, and add a layer of cottonseed meal or blood meal to the soil before adding the mulch. Also, keep the bark away from foundation plantings or risk termite problems. And check that the mulch does not include the bark of black walnut trees, whose toxins can kill azaleas, rhododendrons and tomatoes.

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