Mulching protects soil and crops

Mulching makes use of farm wastes for ground cover to protect the soil, thereby, husbanding the plants grown on them, too. It prevents rapid runoff of rainwater and minimizes damages of heavy watering which creates puddles that stop microbial action. During dry season, mulch conserves moisture while keeping light top soils from being carried as dust by the wind. Other than those, it slows down weed growth, allowing plant growth to gain headway as it prevents moisture- and nutrient robbing competition of weeds and grasses.

Mulch also regulates temperature by protecting the soil from the sun in hot weather, and slowing down the cooling process in cold weather. Upon decomposing, mulch contributes extra humus to the soil.

Nature provides all the organic mulch materials for free. Labor and patience in gathering them is all that is needed. There is not one perfect mulch as all farm wastes are good materials. Use whatever is handy, such as leaves, grass cuttings, tree prunings, coarse sawdust, wood bark, wood chips and shavings, farm leftovers, corn stalks and cobs, papaya trunks and leaves, green coconut husks, plant residues, sugarcane bagasse and many others lying around in the farm.

While small-sized mulch materials may be used directly, it is preferable to shred them further to speed up the humus building. Right after its use in a cropping cycle, it can easily worked into the soil to become part of the soil building process as nature meant it to be.

Speed of decomposition is the most important point in soil building. Big amounts of mulch may be worked into the soil particularly during break in the cropping cycle after serving as protective soil cover. The amount, however, depends on three factors: soil type, amount of moisture and soil temperature.

Decomposition of organic mulch materials occur fastest in light soil under moist but not extremely wet conditions at moderate temperatures. If the soil is well drained and tends to be sandy or sandy silt with adequate rainfall, with at least 100- to 120-day growing season, 10 cm of fine shredded mulch can easily be worked into 20 cm of soil.

The same amount of mulch is needed for well-drained heavy clay soil. However, if it is in a flat area with poor drainage and a tendency for water to stay after the rain, it is advised to use less mulch. Microorganisms need air and water to work and too much water eliminates air and stops microbial action.

Too much mulch does not damage the soil but it reduces productivity because plants draw nutrients from already decomposed materials such as compost and not from fresh mulch. Mulching the entire farm after working the compost into the soil helps conserve moisture and nutrients in the soil and accelerates decomposition while acting as weed killer or weed retardant. Use all the available mulch, however, before planting the next crop, remove much of it and leave some. Leaving some mulch does no harm as it would also eventually decay.

On most vegetables, mulch when convenient–when planting or when plants are tall enough. Even with tomato and corn mulching is not harmful but if put too early it can delay ripening. The same is true for other plants which needs ripening. In some cases, this can be good for the farmers because it prolongs the harvest season and farmers can wait out the early glut when prices are low. Light and medium mulching, for instance, assures early and medium term harvesting without having to stagger the planting.

Here are some mulching practices for corn and a variety of vegetables.

Corn. Allow the soil to warm up and the plants to have a good start before mulching lightly. The plants should be 10-15 cm high. Increase the mulch gradually when the tassels begin to appear, and heavily when the ears develop.

Asparagus. Mulch sections or rows of asparagus to program the shoots for cutting over a longer period. Use mulch heavily: 10 cm of shredded materials or 20 cm of loose materials. For weed control, mulch the patches heavily after cutting is finished and leave the mulch on over long periods, particularly during the rainy season.

Beans. Use 10 cm of fine shredded straw mulch for weed control after the plants have broken through the ground. For dry season planting, use more mulch to conserve soil moisture, especially when rainfall is much too low for desirable plant growth, or when beans are planted as dry-season crop.

Cabbage. When setting the transplant, tuck about 5 cm of mulch close to the plants to conserve moisture while the transplants are establishing themselves. Build it up gradually to 10 cm as the plants grow with straw and grass clippings. Mulch lettuce, cauliflower, brocolli, chinese cabbage, pak choi, pai tsai, kale and mustard the same way.

Carrot. A light shredded mulch over carrot rows protects the soil from baking or crusting, a condition that prevents the tiny plants from breaking through. Upon the sprouting of the seeds, pull back the mulch to give them a chance to grow. When the plants are already well established, push back the mulch closer to the seedlings. Other root crops such as radish, beet, parsnip, turnip and rutabaga are similarly mulched.

Cucumber. A generous amount of mulch conserves moisture and controls cucumber beetles. When the plants are about 10 cm high and spreading their first big leaves, place a 60 cm ring of mulch around each plant at a depth of 10 cm. As the plant spreads, keep adding to the mulch ring so that the vine grows and lies atop the mulch. For similar creeping plants, mulch in the same manner.

Eggplant. This shallow rooted plant needs moisture-saving mulch with weed control as bonus. Mulch with any shredded material as soon as the plant emerges; increase the amount as the eggplant grows.

Onion. Lightly mulch the plots or rows after seeding. As soon as the plant pushes through, slightly pull back the mulch to give the plant more space to grow. After thinning, push back the mulch and gradually increase the amount as the plant grows.

This method applies, also, to garlic, spring onion, bunching onion and leek.

Spinach. Alkaline or neutral conditions with pH range of 6.0-7.5 suit this plant. Do not mulch until the plant have leafed out well and are about 5-6 cm high. Use only finely shredded straw or grass clippings. Water cress and other similar leafy vegetables are mulched the same way.

Sweet pepper. Mulch the young plants lightly when they are about 10 cm high. Increase the amount as they grow to maintain a good level of moisture. Mulch the rows or patches some more where you desire to delay fruit ripening. Other sweet pepper varieties like cayenne, capsicum and jalapeño can be similarly mulched.

Tomato. Mulch lightly and increase the amount as the mulch settles. Make sure a weed-free clean mulch is used in a bed of 10-15 cm under the plants so that when the plants and fruits mature, the plants are not disturbed with constant weeding, thereby, assuring that the plants have plenty of moisture for juicy growth for more succulent fruits.

Watermelon. This plant is a heavy user of moisture and the fruit is like a water storage tank. Mulch is very valuable in retaining soil moisture needed most by the plant particularly during the hot summer months when the crop is grown. Apply mulch of shredded leaves and/or straw when the soil has warmed up and the plants start to spread. Use 15-20 cm cover over the entire area and tuck right up to the growing plants. Vines such as squash, pumpkin, cantaloupe and honeydew are mulched in the same manner.