Nitrogen Fertilisers

Nitrogen fertiliser: which one, and when

Nitrogen is the nutrient plants use most and the one gardeners most often get wrong: too little and growth stalls and pales, too much and you get soft, sappy leaf at the expense of flower, fruit and flavour. The nitrogen fertilisers here are plant-derived. The nitrogen comes from plant proteins and is released as soil life breaks them down, so it feeds steadily over weeks rather than in one soluble hit, and it does not scorch when used at the stated rate.

Which nitrogen fertiliser

• Organic Nitrogen Fertiliser, 13% N. The high nitrogen fertiliser for leaf crops, hedges, and any plant that has gone pale and stopped. Granular, slow-release, plant-based.
• Organic Liquid Nitrogen Fertiliser, 10% N. Amino-acid nitrogen through the watering can or sprayer, for a faster response and for containers.
• Alfalfa Meal Pellets. Lower analysis, gentler release, and a food for the soil biology at the same time. The traditional rose grower's choice; alfalfa meal as an organic fertiliser explains why.
• Organic Amino Acid Fertiliser. Water-soluble amino acids for foliar feeding, where a plant needs nitrogen it can use immediately.

Nitrogen for lawns

Grass is the hungriest crop of all for nitrogen, because you cut its leaves off every week. Organic Lawn Fertiliser 10-3-3.5 is the granular lawn feed built around it, and Organic Liquid Lawn Feed 7-2-3 the liquid alternative for a quicker green-up mid-season. When a lawn needs high nitrogen, and when to stop covers timing through the year, and the whole programme is in lawn care.

For the leafy crops on a plot, Vegetables & Allotment puts nitrogen alongside the rest of the programme; the full liquid range is in Liquid Fertiliser.

When not to use it

Do not feed nitrogen to anything you want to flower or fruit in the next few weeks: tomatoes once the first truss has set, roses coming into bud, strawberries in flower. Do not feed it to root crops at all, or you will get leaf and forked roots. And do not feed it into late autumn, when soft growth is the last thing a plant wants before winter. The best organic fertiliser high in nitrogen and high nitrogen fertiliser: when it helps and when it harms cover the judgement calls.

Common questions