By Beth Asher
Using plastic mulch is one way to keep strawberries clean and weed free. Plastic mulch comes in rolls that go down easily over hilled strawberry rows. Hold down plastic mulch by weighting or staking with a product like Earth Staples. Breathable plastic mulches (usually made of recycled plastic) that allow air and water to reach the soil are best. Using impermeable plastic mulch requires installing drip irrigation underneath or watering by hand.
Put the roll of plastic mulch down at one end of a row with the middle of the hill at the mid-point of the mulch roll. Unroll it out to the other end of the row and down over the end of the hill. Cut the mulch off at the end of the row and stake or weight it down.
Measure the width of your strawberry hill. Eighteen to 20 inch wide hills can support double strawberry rows. 12 inch wide hills will support one row. Using raised beds mulch can be rolled out flat where the strawberries will be planted.
Start at one end of a row and measure along the middle of the hill for single row strawberries. Make a 6 inch wide “X” shaped cut in the plastic every 12 inches to allow for planting.
Measure across the hill at each end to find the mid-point for double row planting. Using a chalk line kit snap a line along the center of the hill. Measure along the middle of the hill in 12 inch increments. At every 12 inch mark measure out 6 inches to either side of your line and cut a 6 inch wide “X” in the plastic. This will give you 12 inch spacing between the strawberries when planted.
Choose everbearing or day-neutral strawberries for growing under plastic mulch as they produce few runners. Cut off any runners that do sprout after planting.
Peel back the mulch at each “X” and dig a hole for the strawberry. Plant strawberries with roots down and slightly spread. Do not bend the roots to the side. Make sure the top roots are just under the soil surface.
Set strawberry plants so the middle of the crown (where roots meet the leaves) is at the level of the soil. Planting too deeply will cause rot, too high and plants will dry out. Fill the holes and firm up leaving no air pockets. Water immediately and set a watering schedule for the growing season.
Plastic mulches warm the soil making them a good alternative in colder climates.
Roll up plastic mulch in winter to prevent freezing and cracking.
Use black or colored plastic since clear plastic allows weeds to germinate underneath and compete with strawberry plants.
Unlike organic mulches that break down over time inorganic plastic mulch will add no nutrients to your growing beds.
Plastic mulches can retain too much heat in hot climates so shade cloth may be required.
Using organic coverings on plastic mulch for looks may block evaporation and cause moisture that will rot strawberry roots.