Fertility plan, step by step

1. What a budget is

A nutrient budget is like household accounts: you add up what the soil receives and what is taken from it.

1. Income and outgoings — Income is compost, manure, green manures, urine, ash and mulch. Outgoings are the vegetables, fruit, hay and grain you take away.
2. When it doesn't balance — When income is lower than outgoings, the soil gets poorer. When it is much higher, the surplus goes into the water: nitrate from nitrogen into the well.
3. Three nutrients — Nitrogen shortage: pale, yellow lower leaves. Phosphate: purple leaves and slow growth. Potash: brown edges on older leaves and small fruit.
4. Field and gate — The field budget asks what each bed needs this year. The farm-gate budget asks what comes onto the homestead from outside and what leaves.

Why: On one bed the vegetables turn yellow from hunger, while on another there is too much phosphate and nitrogen trickles into the well. Both problems have the same cause: nobody added up income and outgoings.

• A budget asks three questions: how much the crop needs, how much the soil and fertilisers supply, and what is short or in surplus.
• The field budget tells you what to do in spring; the farm-gate budget tells you whether the homestead is getting poorer, or polluting, over the long run.

2. The soil test

Without a soil test, the budget is just guesswork about phosphate, potash and acidity.

1. Always the same — Take the sample from the same spot, at the same time of year, ideally in autumn before manure and lime, and send it to the same lab. A soil test every 3–5 years.
2. pH first — For a vegetable garden, pH 6.0–7.5 is good. Below 6, lime or ash first; above 7.5 the soil is chalky, so no ash and no lime.
3. Organic matter — 3–5 % organic matter or more is good. Below 2 % you need more compost and green manures for several years.
4. P and K index — Indices and classes run from very low to very high. Compost and manure improve low phosphate; when it is very high, no manure and less compost. Record the results over the years.

Why: Labs report phosphate and potash in different units depending on the method: in the UK in mg/L with an Index from 0 to 9, in Ireland Morgan's test with an Index from 1 to 4, in the US usually in ppm with a class. The boundaries depend on the method and the lab, so use the index or class from your own report.

• Ask for a fertiliser recommendation for a vegetable garden, not for a wheat field.
• How to take a sample and where to send it is in module H02-01 Soil testing: home tests and the lab.

3. Need and supply · Locked

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4. Example: 10 m² of cabbages · Locked

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5. Phosphate, potash and humus · Locked

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6. Homestead and zones · Locked

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