Geotextiles: Red Plastic
Red plastic mulch’s touted strength is in its ability to re!ect certain red shades of light back into the plant, accelerating fruit production and increasing yield. Specifically, when far-red light wavelengths from the plastic bounce back up to tomato plants, the phytochromes tell the tomato fruit to grow more and faster.
Use
Red plastic mulch is typically used for spring-seeded crops because it increases soil temperatures about 4-6ºF at a depth of 2 inches compared to bare ground.
Installation
Red plastic mulch can be laid both by hand or with a plastic laying machine which is a tractor implement.
- 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.
Pros
Here are some of the advantages you can expect:
- Earlier and higher yields Red mulch reflects intensified red light to the developing plants, which increases their photosynthetic capacity. More light is reflected early in the season when plant foliage covers less of the mulch, allowing plants to grow more quickly and yield earlier. Tomato yields have increased as much as 20% higher with SRM-Red as compared with black plastic, in some studies.
- Weed control.
- Soil temperature increases 4° to 6°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.
Cons
Here are some disadvantages to consider:
- Increased cost. Red plastic mulch is more expensive than other mulches. 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 different opinions on red plastic mulch. Studies of red mulch have not shown consistent results nor do farmers have a consistent opinion. Red mulch sometimes increases yield of tomatoes, but not always. Different tomato varieties also appear to respond differently to the red mulch. Additionally, some farmers have noted that red plastic allows vigorous weed growth.
Where To Buy
Red plastic can be found easily. Try Harris Seeds.
Sources
‘SRM Red Plastic Mulch’ www.kenbar.com
‘Plastic Primer’ VT Veg and Berry Factsheets uvm.edu
‘Review: Red Plastic Mulch for Tomatoes–Does It Make a Difference?’ www.tomatodirt.com