Control weeds and protect your garden during harsh summer by mulching
September 1st, 2016 | Tasawer Abbas, Dr. Muhammad Ather Nadeem, Prof. Dr. Asif Tanveer and Ali Zohaib T | No Comments
There are many reasons to use mulch in your garden. Mulch keeps weeds down, improves soil
structure and makes your garden more attractive. Another big plus for using mulch is that it
prevents water loss by evaporation and conserves the amount of water you will have to use in the
summer and reduce water consumption in summer. Mulch also reduces the temperature in root
zone by covering the soil that prevents direct sun light to soil surface. Therefore it has potential
to protect plants during hot dry day in summer.
Mulch is any physical material you place over garden soil to affect either the soil or the plants
growing there. Mulch is of two types: organic mulch and inorganic mulch. Organic mulches are
derived from plant materials that eventually decompose and become part of the soil. For
example, plant leaves, straw, grasses, remaining fodder etc. Inorganic mulches include both
plastic sheeting of various kinds and gravels. Different kinds of mulches have very different
effects. In some cases a mulch may actually do the opposite of what you intend it to do. So itand#39;s a
good idea to do a little homework before you make a choice. For example, use of plant mulch
that has strong allelopathic potential may suppress the growth of desired plants in the garden.
Foot traffic, weather and even the impact of raindrops tend to compact the top layer of bare soil,
making it more likely that rain will run off rather than soak in. Good mulch reduces the
compaction and allows the water to infiltrate the topsoil layer slowly and effectively. Organic
mulches, such as wood chips, compost, sawdust or even straw, usually allow soil to be more
absorbent to rainwater than bare soil.
Once the soil layer is moist, a layer of mulch helps to keep it from drying. With bare soil, the
heat of the sun causes the top layer of soil to heat up, causing water in the soil to evaporate. As
the moisture in the top layer of soil evaporates, more moisture wicks up through the soil to
replace it, until the soil is essentially dry. A coarse organic mulch layer reduces soil
temperatures. In addition, water canand#39;t wick well across the interface between the soil and mulch.
So the surface of the soil stays moist longer and much less water is lost to evaporation.
A layer of mulch can cut down evaporation by as much as 75 percent. Gravel can also be an
effective mulch to conserve water. It lets rain or irrigation water through readily and reduces
evaporation from the underlying soil surface. White gravel, because it reflects the sunand#39;s heat, is
usually the most effective gravel at keeping soil temperatures down, consequently reducing
Woven plastic sheets called geo-textiles or landscape cloth allow water and air to penetrate the
soil and effectively reduce evaporation. Theyand#39;re also good at suppressing weeds. On the other
hand, they usually need to be covered by an additional layer of organic bark for aesthetic
reasons, and they donand#39;t eventually decompose and improve the underlying soil the way organic
andquot;Beware also of weeds that can germinate and grow on top of the cloth in the decomposing
mulch,andquot; warned Bell. andquot;Plastic sheets, while effective at weed control, are not good at allowing
water and air to penetrate the soil.andquot;
The best time to apply mulch for conserving water is while the soils are still well charged with
winter moisture in the spring. Once theyand#39;ve dried out thoroughly in the summer heat, much of the
benefit of the mulch is lost for the season.
Here are some things to do before mulching. If the soil is compacted, roughen it up to aerate it
and make it easier for water to penetrate. Add any soil amendments that youand#39;re planning to use
before placing the mulch.
A two-inch layer of organic mulch is usually enough for weed suppression and moisture
retention. If you already have a layer of mulch in place, wait until itand#39;s decomposed to add more.
Try raking it up to aerate it and freshen its appearance. Do not apply too thick a layer, which can
keep oxygen from getting to the roots of shrubs and trees. While mulches can be very effective in
reducing evaporation, they canand#39;t stop it altogether. So if you want to conserve water, donand#39;t forget
to group plants together according to their need or lack of need for water. Choose new plants that
are drought tolerant. Plan and plant for shade in your garden.
Published in: Volume 07 Issue 30
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