How often should I feed through the season?

Most feeding mistakes come from applying one regime to a situation that needs another. A plant in good open ground rarely needs feeding at all; a plant in a pot always does, because every watering flushes nutrients out of the bottom. Once those two are separated, almost everything else follows.

Safety

Step by step

1. Separate the three regimes before anything else.Plants in decent open ground, fed by the soil. Plants in containers, fed entirely by you. And anything you want to flower or fruit heavily, which needs the balance changed part way through. These need different answers and merging them is what causes both over-feeding and under-feeding.
2. Open ground: one balanced feed in early spring.As growth starts — a general balanced fertiliser at the pack rate, raked into the surface, on beds carrying hungry crops, roses, and fruit. On established shrubs and perennials in good soil, even this is optional.
3. Open ground: a compost mulch in late autumn or late winter.Twenty-five to fifty millimetres. This is soil improvement rather than feeding, and over a decade it does far more for a border than any bottle does in a season.
4. Containers: granules at planting.Controlled-release granules mixed into the compost when you plant, at the pack rate. They cover roughly the first three to six months depending on the product and the weather.
5. Containers: weekly liquid feed from six weeks in.Bagged compost's built-in feed runs out at four to six weeks — sooner in peat-free wood-fibre mixes. From then on, weekly liquid feed at label strength, or twice weekly at half strength, until the end of August.
6. Flowering and fruiting: switch at first bud.Balanced or slightly nitrogen-leaning while the plant is building leaves and stems. High-potash from the moment flower buds appear, weekly, until the crop finishes. This one switch does more for a tomato crop than anything else you can do.
7. Stop nitrogen at the end of August.Nitrogen applied late pushes soft growth that will not harden before the first frosts, and that soft growth is what gets killed. Late-summer feeding should be potash-led if it happens at all.
8. Feed nothing dormant.From roughly October to February most plants are not growing and cannot use anything you apply. Fertiliser applied then leaches away, or accumulates as salts in a container. Houseplants and anything growing under protection are the exception.
9. Never feed a plant in trouble.Wilting, yellowing from waterlogging, newly transplanted, root-damaged or drought-stressed. Feeding a stressed plant concentrates salts around roots that cannot take up water and makes everything worse. Fix the cause, wait for growth to resume, then feed.
10. Water before feeding, always.Fertiliser onto dry roots burns them, and in a dry pot the liquid runs straight down the sides and out. Water, wait a few minutes, then feed.

Tips

• Half strength twice as often is better than full strength half as often, in containers particularly. It smooths out the supply and greatly reduces the risk of scorch.
• Hanging baskets and window boxes are the most demanding thing in a garden — small volume, constant watering, heavy flowering. They want granules at planting and weekly liquid feed without fail.
• A plant that has stalled in midsummer in a container is almost always out of feed rather than diseased. It is the single commonest container problem there is.
• Feeding a lawn is a different calendar again — high nitrogen in spring, low nitrogen and high potash in autumn — and lawn feeds often contain herbicide, so they must not go on beds.
• In a wet summer, liquid feed in containers leaches faster and the interval should shorten rather than lengthen.

If it doesn't work