Black plastic mulch and landscape fabric are also well-known synthetic covers for suppressing weeds, conserving soil moisture, raising soil temperatures, and increasing crop productivity (Kasirajan and Ngouajio, 2012).
Using black plastic can be an easy way to start a garden. It helps control weeds and conserve moisture. In cooler climates, black plastic will raise the soil temperature, allowing to get your garden started a bit earlier. By growing your vegetables in plastic, you can save time by weeding and watering much less often.
Non-permeable covering like plastic sheets will interfere with the exchange of air, water, and nutrients between the soil and the atmosphere. This means the product will not only smother the weeds but will also smother the crops. The plastic sheet could raise the soil temperature too much so cut slits for the plants.
Black ground cover acts as an effective weed barrier for your plants. Using polyethylene for coving plant bedding keeps light from reaching the weeds underneath and stops them from growing and ruining your harvest.
In general, transparent or clear plastic is most effective for solarization, as the heating rays from the sun will pass through the sheet and be trapped to heat the soil below. Usually black plastic is less effective because it absorbs and deflects part of the heat, rather than trapping as clear plastic does.
Transparent or clear plastic is most effective for solarization. Black plastic, often used for mulching, does not heat the soil as well as clear plastic. It can be used for solarization but its main effect is reducing weed growth.
Black plastic mulching is only advisable to use for heat-loving vegetables like melons, tomatoes, peppers, and other summer crops. Never use black plastic mulch for growing cool-season crops, such as lettuce, peas, and tubers. Excessive heat will kill these crops.
Root girdling can lead to poor tree health and even tree death. Additionally, groundcover plants might also contribute to tree rot caused by the build up of moisture, debris, and plant material underneath.
Weed control. Mulch helps prevent the establishment of weeds in many vegetable crops. Black sheet mulches prevent most weeds by excluding light. Intact plastic and other materials control essentially all annual weeds except at planting holes and mulch edges, where additional control measures are needed.
Black plastic mulch is typically used for spring-seeded crops because it increases soil temperatures about 5ºF at a depth of 2 inches compared to bare ground. Black mulches absorb heat from sunlight then pass it on to the soil below.
Toxic effects
Chlorinated plastic can release harmful chemicals into the surrounding soil, which can then seep into groundwater or other surrounding water sources, and also the ecosystem. This can cause a range of potentially harmful effects on the species that drink the water.
Plastic bags are non-biodegradable in nature. It remains in the soil for a long period of time without getting decomposed. It prevents seeping of water into the soil and thus prevents the growth of plants. Thus, plastic bags pollute the soil and are considered bad for the soil.
Size matters when it comes to microplastics in plants
At that size, it's easy to imagine how plants could absorb plastic particles, but there are size limits regarding what passes through cell walls. Generally, healthy adult plants only absorb materials 3–4 nanometers in size, which is even smaller than a virus.
Landscape fabric has a longer lifespan as it's usually a treated, synthetic material made from polyester or polypropylene. Its composition makes it resist degradation. Black plastic mulch, on the other hand, easily breaks down when exposed to direct heat or sunlight.
The most common mulch used is white on black. The black side reduces weed germination, and the white top reflects solar radiation this cooling the surface and the soil beneath.
For vegetable gardens, another option is to simply cover your garden beds with black plastic or a layer of cardboard or even an old carpet, leaving it in place through the winter season and up until you're ready to plant in spring. This will kill existing weeds and subdue sprouting seeds.
So remember, if you want healthy soil – keep it covered. Soil surface temperatures under residue-covered soils can be 40 or more degrees cooler than bare tilled surfaces.
I've been mulching with black plastic for many years now. The trick to watering is to run a soak hose/ weeping hose under the plastic and about 8-10 inches from the plant stem. I put out a 12-inch round, 1-inch deep dish, ran the soak hose over it, and timed how long it took to fill with water.
Pebbles, bark, slate and gravel are all very simple to lay - making them popular ground cover aggregates.
Landscaping fabric adds no nutritional value to the soil, and it doesn't decompose. And over time, the fabric can be detrimental to your soil's health. Biodegradable alternatives like shredded leaves, cardboard, and compost are healthy foods for the soil –– and the hungry earthworms!
Black plastic is actually the strongest against sunshine.
This means that black can stand being in the sun longer than any other color.
We have found temperatures of over 140°F at the surface of black plastic mulch. This can cause losses with transplants because stems near the mulch are damaged by the high heat. In crops seeded through the black mulch, germination is often reduced, and if plants do emerge, they can be killed by the excess heat.
During the day, sunlight heats the black plastic and heat is transferred by conduction to the soil. At night, soil heat is lost by conduction through the plastic mulch, but water condensation reduces heat loss.