We are heading out for a long backpacking trip in Idaho this week. But while we are gone we don't want our garden to fry in the hot weather, but we won't be able to water either since we obviously won't be here. Here is our solution to dealing with this conundrum with our thirstiest crops (such as the celeriac shown below).
We decided to mulch to preserve moisture (a good technique to use any time during the heat of summer to conserve water...and increase crop yields). We used comfrey (Symphytum spp.) leaves because they are free and plentiful and when they break down they release nutrients such as nitrogen, potassium, and phosphorus and many minerals that comfrey is able to mine from the subsoil with it's long taproot. So in addition to saving water, this mulch is like free fertilizer, and as it breaks down it will add organic and help to improve the soil. We also spread some free compost from the Kailash Ecovillage kitchen compost system on top of the leaves because it will also help to fertilize and improve the soil way (plus we needed something on top of the leaves to keep them from blowing away). Here is our step by step guide:
Step 1: Harvest some comfrey leaves. (These are photos from Kailash Ecovillage but the actual comfrey we harvested was from the Reed College campus where it is growing as a weed).
Step 2: Water the crop well. In our case we had a few days of heavy rain that did the job for us. Just make sure that your soil is already moist before you begin.
Step 3: Optional. Fertilize the garden crop. (On our hungriest crops such as the celeriac we side-dressed with a mix of alfalfa meal, rock phospahte, lime, and rock dust before multching).
Step 4: Lay out the comfrey leaves around your plants so that no bare soil is showing.
Step 5: Cover the comfrey leaves with a thin layer of compost.
And voila, it is mulched. Now we don't have to worry about watering quite as often as the days begin to warm up. Hopefully this will be of use to someone out there in the blogosphere.