Geotextiles: Olive Plastic or IRT
Olive plastic is the latest development in plastic mulch technology, offering a hybrid between clear and black mulches. It offers more soil warming than black mulch, while controlling weed growth better than clear mulch. Clear mulch transmits all wavelengths of radiation (light) to the soil, therefore warming the soil better than any other plastic. However, it is responsible for vigorous weed growth under the plastic.
By utilizing a carefully balanced blend of polyethylene with a specific light modifying pigment, olive plastic simultaneously generates almost as much heat as clear mulch and suppresses weeds like black mulch. Plastic simultaneously generates almost as much heat as clear mulch and suppresses weeds like black mulch.
Olive plastic mulch is typically used for spring-seeded crops because it increases soil temperatures about 8-10ºF at a depth of 2 inches compared to bare ground. Olive plastic can be used for a number of crops in the home garden or on the farm especially crops that like warmer temperatures including watermelon, cantaloupes, cucumbers, peppers, and pumpkins.
Olive plastic mulch can be laid both by hand or with a tractor.
- Prepare soil well. It should be smooth and friable.
- If using drip tape, be sure it is laid well and it must go underneath the plastic.
- Do not lay plastic on dry soil.
- Carefully adjust plastic laying machine so the plastic is laid evenly on the bed having equal amounts on each side.
- Plastic should be in close contact with the soil for maximum heat transfer into the soil.
- Be sure the edges of the plastic are well secured with soil.
- Be careful not to puncture the plastic, as any holes allow sunlight to permeate and encourage weed growth.
Here are some of the advantages you can expect:
- Earlier and higher yields than black mulch. Melon yields have shown 25% increases in yield with olive mulch.
- Weed control.
- Soil temperature increases 8° to 10°F under the mulch at soil depths of 2 to 6 inches.
- Evaporation of soil moisture is reduced. Plastic mulch is impervious to water. It is particularly effective when used in combination with drip tape. Any evaporation of soil moisture occurs only through the planting holes.
- Nutrient leaching is reduced during excessive rainy periods.
- Easy to install and durable. Plastic mulch is flexible and stretchable. It will conform to both flat and raised beds. Strong enough for double cropping in the same season or possibly for use over two seasons.
- Easy field removal.
Here are some disadvantages to consider:
- Increased cost. Green plastic is more expensive than black plastic. All plastic mulches are expensive to buy, install and clean-up.
- Removal and disposal. This plastic must be removed and disposed of at the end of the season. This requires significant time.
- Farmer experience shows that there may be little observable difference in the amount of soil warming between black and olive plastic mulches. Many farmers choose black mulch over olive mulch, despite the slight warming effects, because it is cheapest and they use it so widely on the farm. It is easier for farmers to stick with one trusted plastic mulch than have many varieties for different crops.
Where To Buy
Olive plastic is widely available at many garden supply sources.
‘SRM Olive Plastic Mulch’ www.kenbar.com
‘Use of Plastic Mulch and Row Covers in Vegetable Production’ Oklahoma Cooperative Extension osufacts.okstate.edu