Terraseed prevents weed seeds from germinating below the seed mat but does not stop perennial weeds establishing from residual plant material (tubers, roots etc).
Terraseed Classic and Terraseed Excel both give excellent weed control providing there are at least 40 plants / m2 to keep the mat in contact with the soil. At lower plant densities the seedmat can become detached from the soil surface, which creates an air pocket that allows weed seedlings to establish.At higher plant densities complete weed control can be expected providing vigorous, fast germinating crops (like baby leaf lettuce) are being grown.
Some herb crops (eg parsley) take a very long time to germinate , allowing the seed mat to lose its contact with the soil and weed seedlings to establish. Consequently, Terraseed is not recommended for all crops and plant spacings. Specific guidance on recommended crops is available.
It is essential to lay Terraseed onto either a freshly prepared bed (ie within 24 hrs of cultivation) or onto a stale seedbed where seedlings have been killed by burying or herbicide application. Once a seedling has established then Terrassed will not stop it growing!
 How a thin blue plastic film laid on the soil surface effectivey controls weeds is not entirely understood. The best explanation we have been given is that the ratio of red and far red light passing through the blue layer is modified. This effects the phytochrome system responsible for plant growth and germination. However, if contact between the soil and the seedmat is lost then this effect is lost.
New combinations of materials are constantly being evaluated to enhance crop production and weed control. The most recent focus is on the use of dark plastics for the upper layer and increased pigmentation in the lower paper layer. |
