Fertilising vegetables correctly
Vegetables need nutrients to grow strongly and crop well – but the right amount is decisive. Too little leads to stunted growth, too much makes the plants soft, susceptible to pests and can even harm the harvest. Anyone who knows what their plants need fertilises purposefully and sparingly.
The most sustainable approach is organic fertilising with compost and the like, which nourishes not only the plants but also the soil life.
In short
- The main nutrients are nitrogen (leaf), phosphorus (root/flower) and potassium (fruit/resilience).
- Heavy feeders need a lot, light feeders little – crop rotation uses this.
- Fertilise organically (compost, horn shavings) to nourish plant and soil.
- Do not over-fertilise – too much nitrogen attracts aphids and does harm.
The most important nutrients
Nitrogen (N) promotes leaf growth, phosphorus (P) roots, flowers and fruit, potassium (K) fruit quality and resilience. Added to this are magnesium, calcium and trace elements. A deficiency often shows on the leaves – for example yellowing with a nitrogen or magnesium deficiency.
Heavy, medium and light feeders
- Heavy feeders (high nutrient demand): tomato, cucumber, pumpkin, cabbage, celery – supply well with compost.
- Medium feeders: lettuce, carrot, onion, kohlrabi, beetroot – fertilise moderately.
- Light feeders: beans, peas, herbs – hardly any fertilising needed; legumes even enrich the soil with nitrogen.
Organic or mineral?
Organic fertilisers such as compost, horn shavings, plant liquid manures or well-rotted manure release their nutrients slowly and encourage the soil life – ideal for the home garden. Mineral fertilisers act fast but carry the risk of over-fertilising and do not nourish the soil. For healthy, sustainable gardening, organic is the better choice.
Frequently asked questions
When should I fertilise?
Base supply with compost before planting, then top up heavy feeders during the season every few weeks (e.g. with nettle liquid manure).
How do I recognise over-fertilising?
By lush, dark-green, soft growth with little fruit and heavy pest infestation.
Tip
Home-made nettle liquid manure is an excellent, free nitrogen fertiliser for heavy feeders – diluted (1:10) and watered on, it works wonders.
Caution
Less is often more: over-fertilising does more harm than a slight nutrient deficiency – it encourages aphids, rot and, in tomatoes, blossom-end rot.
Strong young plants use the nutrients optimally. We raise our young plants healthy and robust.