Brunnings Urea, what it does and when to use it

Urea is the strongest straight nitrogen fertiliser you can buy off a shelf, at around 46% nitrogen, and that is the whole story with it. It is cheap, it works fast, and because it is that concentrated it is also the easiest fertiliser in the shed to get wrong. So here is what it does, what it does not do, and how to put it on without scorching anything.

What nitrogen actually does

Nitrogen drives leaf. That is it. A lawn that is pale, thin and slow to grow is very often short of nitrogen, and urea is the quickest way to answer that, which is why you see the colour lift within a week or so.

A thicker lawn also crowds out weeds on its own, so feeding the grass properly does more for weed control than most people expect.

What urea is not

This is the part that usually gets left out. Urea is nitrogen only. There is no phosphorus in it and no potassium, so it is not a complete lawn food and it will not fix a lawn that is struggling for any other reason.

If your lawn is thin because the soil is compacted, or because it is in too much shade, or because the pH is out, urea will give you a brief flush of green and the problem will still be there. Potassium in particular is what makes grass hardy through heat and cold, and urea gives you none of it.

So think of urea as the specific tool for a specific job, and a complete lawn fertiliser as the thing you use through the year.

Do not put it on flowering plants or fruiting vegetables

Nitrogen tells a plant to make leaves, so a tomato, a capsicum, a zucchini or a rose given a dose of urea will put its energy into foliage instead of into flowers and fruit. You end up with a magnificent green plant and very little to eat.

Leafy crops are the exception and they love it. Silverbeet, lettuce, spinach and brassicas are all leaf, so nitrogen is exactly what they want.

How to apply it without burning the lawn

• Use a spreader, or split the bag. A concentrated handful in one spot will kill the grass under it. Even coverage is most of the job.
• Water it in properly, the same day. Two reasons. It stops the granules sitting on the blades and burning them, and urea left on the surface turns to ammonia gas and simply blows away, so an unwatered application is money on the lawn doing nothing.
• Not onto a dry or heat-stressed lawn. Give it a water first if the ground is bone dry, then feed, then water again.
• Not in the middle of a hot day. Early morning is the time, so it can be watered in and dried off well before evening.
• Read the rate on the bag and stick to it. More is not faster with urea, more is burnt grass.
• Keep kids and the dog off it until it has been watered in and the lawn has dried.

Store it somewhere dry and closed up. Urea pulls moisture out of the air and a half-used bag left open turns into a solid lump.

When to use it

Spring and early autumn are when a warm season lawn is actively growing and can use the nitrogen. Feeding hard in the middle of winter, when the grass has gone dormant, mostly just feeds the weeds.

If in doubt, start with less than you think. A lawn that needed more is an easy fix a fortnight later. A lawn that got too much is a few weeks of brown stripes.

Shop related products

• Brunnings Urea 2.5kg. Straight nitrogen for a pale, slow lawn or for leafy crops.
• Neutrog Sudden Impact for Lawns 10kg. The complete lawn food for the rest of the year.
• Brunnings Potash Power 2.5kg. The potassium urea does not give you, and what makes grass tough.
• Seasol Seaweed Concentrate 1L. A tonic rather than a fertiliser, and useful on a lawn that has had a hard summer.

Did you know we also keep sulphate of potash, garden lime in 3kg and 10kg, and Neutrog Blade Runner lawn fertiliser in store, and not all of that is listed on the website. Give us a ring on (08) 8536 4333 or come in and we will work out what your lawn is actually short of.

The rest of the garden range is on the website, and the garden centre is worth a look when you are in.

More from the garden

• Organic products for feeding a lawn
• Keeping a lawn green, and what usually goes wrong
• Sudden Impact for Lawns, what it does

Still learning, still of the view that the lawn is mostly there to walk on. Candeece.

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