How much vermicompost per acre? A practical way to decide

There is no universal figure

Every supplier is asked for one number, and the honest answer is that it does not exist. Two neighbouring fields growing the same crop can need very different amounts of compost depending on how much organic matter each has left.

A rate that suits a depleted, sandy soil being brought back into production will overshoot on a field that has had organic matter returned for years. Treating compost like a fixed-dose fertiliser wastes money in one case and under-delivers in the other.

Four things that set the rate

Work through these before deciding how many tonnes to order.

• Starting condition: a soil low in organic matter needs a heavier corrective application than one being maintained.
• Crop and rooting depth: a shallow-rooted vegetable crop responds to less material, placed nearer the surface, than a long-season plantation crop.
• Placement: banding along the row concentrates material where roots will find it and stretches a smaller quantity further than broadcasting.
• Programme length: a correction split across two or three seasons is usually more effective, and easier to fund, than one very heavy application.

Build a programme, not a purchase

The farms that get the most out of compost treat it as a recurring input with a fixed place in the calendar. A moderate application repeated every season builds organic matter more reliably than an occasional heavy one, because the material is being replaced at a rate closer to how fast it is used up.

It also spreads the cost. For most commercial operations, that is the difference between compost being a permanent part of the programme and a one-year experiment.

How to get a figure you can plan around

Tell us the crop, the area, the irrigation setup and, if you have one, a recent soil test. We will give you a rate and a schedule. If your soil does not need what you were planning to buy, we will say so; a customer who orders correctly for five years is worth more than one who over-orders once.