Silver mulch is polyethylene sheeting coated with a thin layer of aluminum and that reflects ultraviolet rays. These UV rays, coming from an unexpected direction, have been found to confuse insects — specifically aphids, whiteflies and leafhoppers — decreasing the chances that they land on and feed on the plants growing on the mulch. Aphids often spread harmful mosaic viruses that render crops inedible.
Crops for Silver Mulch
Silver mulch benefits multiple crops in the garden. It decreases insect and disease damage to tomatoes and delays the onset of aphid-borne diseases in squash, melons, cucumbers and corn until plants and fruit are more mature and less likely to be seriously damaged. Peppers, onions and potatoes all have increased yields with larger fruit when planted with silver mulch, though silver mulch may decrease potato production in cool temperatures. Orange trees also benefit from a decrease in insect damage and in greening when surrounded by silver mulch. Young tomato seedlings — five to seven days old — may temporarily experience leaf burn and stunting when planted on silver mulch, but damage is not severe, and damaged plants soon outgrow those not planted on mulch. Eggplants, however, are not recommended for silver mulch.