Organic Green Manure Phacelia

Green Manure, Phacelia
Latin name Phacelia tanacetifolia
Approximate coverage 1000m² per Kg, 4Kg per acre

Green manures are plants grown specifically to improve the soil. They do this in a number of ways: by being deep rooted; by covering the soil to prevent leaching of nutrients; by fixing nitrogen; by breaking up the soil with fibrous root structures. In all cases they are dug or mulched back into the soil adding organic matter which helps retain moisture and feeds the soil’s beneficial organisms. To dig in chop up the green manure with a spade and turn it into the top few inches, 10-12cm or so, of soil. Mulching out is the easier option, cut down if necessary and leave the clippings on the soil then cover to exclude the light using cardboard and grass cuttings or a biodegradable ground cover. Keep covered for at least 6 weeks, but longer if you do not need the ground, by which time most of the green manure would have broken down and incorporated into the soil by earthworms.
Good soil is the major and underlying principle for organic growing and green manures play a vital role. Use them to cover bare ground particularly over winter.

Phacelia is a quick growing annual with abundant lacy foliage. The leaves are good at suppressing weeds while the roots help to break up and aerate the soil.
Phacelia should be dug in before flowering while the growth is young and soft but allow some to flower as the delicate purple clusters are much loved by bees.

How to grow
Sow March – September
Normally you would have recently harvested a crop from the ground where now you are going to grow green manure. In which case not much cultivation is required. Fork or rake over to get a fairly good tilth and remove any weeds. Scatter the seed over evenly and lightly rake in. Water the seedlings if the weather is very dry.

When to dig in
Dig in or mulch out 6 – 8 weeks after sowing and, for best results, before flowering. Leave some to flower for the bees.