mulch, probably about 4 inchs deep I have seen recommended. Keep it a little away from the stems of the plants. What you can use as mulch is varied and diverse. Spoilt hay, straw, stredded leaves, dried grass (not newly mown), partly composted pine needles, composted saw dust or wood shavingsompost, used coffee grounds, used mushroom compost, sea weed if you can get it, spent hops or corn husks etc etc etc etc. Avoid large and medium chunks of wood, in fact any wood shavings or saw dust that has not been weathered for
2-3 months at least, treated wood products, stone and plastic sheets.rob