Skip to main content
21-0-0

Safety note

Our strongest product. Wear gloves and eye protection, keep it well away from children and animals, and store it sealed in a dry place. Do not apply in hot sun, before heavy rain, or above the stated rate. Rinse skin and eyes thoroughly with water after any contact, and sweep spills up rather than washing them into a drain.

NPKNPK 21-0-0Spring pick

Nitrogen Boost 21-0-0

Ammonium sulphate for a fast green-up on lawns and leaf crops.

Available sizes
Quantity
1 x $28$28
Checkout

About this fertilizer

Straight ammonium sulphate for when a soil test, or plain experience, tells you nitrogen is the only thing missing. Nothing else in the bag, so it corrects one deficiency without adding phosphorus and potassium the ground may already have plenty of.

It acidifies slightly as it works, which is a genuine advantage on chalky or alkaline soil and a reason to be careful everywhere else. This is the strongest product we sell and the easiest to misuse, so read the rate and stick to it.

Recommended uses

  • Lawns that are pale or yellowing but otherwise healthy
  • Leafy crops such as brassicas, spinach and chard
  • Correcting nitrogen shortage confirmed by a soil test
  • Mildly lowering pH on chalky ground
How to apply it

Application instructions

Follow these in order. The rates below are the ones we test to, and going over them will not make anything grow faster.

  1. Confirm nitrogen is the problem

    Uniform pale yellowing on older leaves first is nitrogen. Yellowing between green veins is usually iron or magnesium, and this product will not help. Test the soil if you are not sure.

  2. Apply lightly at 1 lb per 100 sq ft

    That is roughly 2 level cups. Spread it evenly on damp soil or grass, never in a heap, and never at more than the stated rate. This is the one product here that will scorch a lawn if you are heavy handed.

  3. Water in within the hour

    Give the area a thorough soak straight after spreading. Granules left on dry grass in sun will burn the blades within a day.

  4. Leave eight weeks between applications

    Twice a season is plenty. Do not apply after late summer, as soft autumn growth will not harden before frost.

Expires in

Limited time offer

We rebuilt your site for you. Claim it and we handle everything transfer, hosting, and your domain. Then update it anytime, just by asking AI.

Host for only$8 per monthBilled yearly
Claim limited offer now