Comfrey (rich in potash) or nettles (rich in nitrogen).
I use comfrey in three ways.
The first is simply to add it to the compost heap, where its nutrients will both enrich the whole heap and encourage decomposition. Comfrey has a high carbon to nitrogen ratio - ideal for most plants.
The second way is to spread the leaves as a mulch beneath, say, your tomatoes. This acts like any other mulch - slowing down evaporation of moisture and suppressing weeds - but because the leaves rot quickly, it also enriches the soil where the surface roots are.
Comfrey as a mulch - avoid using flowering stems as these can root.
I use comfrey in three ways.
The first is simply to add it to the compost heap, where its nutrients will both enrich the whole heap and encourage decomposition. Comfrey has a high carbon to nitrogen ratio - ideal for most plants.
The second way is to spread the leaves as a mulch beneath, say, your tomatoes. This acts like any other mulch - slowing down evaporation of moisture and suppressing weeds - but because the leaves rot quickly, it also enriches the soil where the surface roots are.
Comfrey as a mulch - avoid using flowering stems as these can root.