Lawn Care

Lawn feed and lawn fertiliser: what grass actually needs

Grass is the hungriest crop in the garden. Cut it every week and it has to rebuild itself from the roots up, every time, which is why a lawn that is never fed thins, yellows and lets moss and weeds in. This collection is the Dr Forest approach to lawn feed: a slow-release organic lawn fertiliser as the base, a liquid lawn feed for a quicker response, a wetting agent for ground that has stopped taking water, and the supporting cast for compacted, tired or stressed turf. Every ingredient is named on the label, and none of it scorches when used as directed.

Which lawn feed

• Organic Lawn Fertiliser 10-3-3.5. The core of the programme from spring to late summer: granular, high in nitrogen, releasing gradually for steady colour and recovery rather than a flush and a slump. For most lawns this one bag is the whole job. When a lawn needs high nitrogen and when to stop explains what the nitrogen is doing.
• Liquid Lawn Feed 5-2-5. The liquid lawn feed for a faster response mid-season, for a lawn that has gone pale after a wet spell, or where you would rather spray than spread. Lower in nitrogen, with magnesium alongside it for colour.
• Autumn is a different job. From September the aim is root and crown condition rather than top growth, so the nitrogen comes off and potassium goes on. The autumn lawn feed, the gypsum and the lime for winter-wet ground are gathered in Autumn & Winter Lawn Feed.

What makes a good lawn fertiliser

The question behind most searches for the best lawn fertiliser is really three questions. Will it scorch? Slow-release organic nitrogen will not, because it is released by soil life over weeks rather than dissolving on contact; soluble synthetic feeds scorch because all the nitrogen arrives at once. How often do I have to do it? Less often than with a soluble feed, for the same reason. And what is in it? On a Dr Forest bag, every ingredient, in full, on the label. Beyond that there is no secret: feed when the grass is growing, water it in, mow a little higher through summer, and deal with compaction and dry patch before reaching for more nitrogen. Nitrogen Fertilisers sets the lawn feeds alongside the other nitrogen options if you want to compare analyses.

When water runs off: dry patch and compaction

Feeding a lawn that water cannot get into is money poured away, so these two come before the feed if either applies. Dry patch is the irregular straw-coloured area that stays hard and sheds water through a dry spell; the soil underneath has turned water-repellent, and the answer is the Natural Wetting Agent, made with soap nuts and aloe vera, applied as a drench and repeated through the summer because the effect sits in the top few centimetres. The lawn wetting agent guide covers how to tell dry patch from drought, timing and method. Puddling after rain is the opposite problem, compaction on heavy ground, and there Liquid Gypsum works beneath the surface to help the clay flocculate and drain without shifting pH; aerate first and you will get more from it. Clay Soil has the fuller set for heavy ground.

The supporting cast

• Soluble seaweed powder or Scottish kelp meal. Trace elements and natural biostimulants that help grass through drought and heat stress; how to apply seaweed fertiliser covers method and timing, and the rest of the range is in Seaweed Fertiliser.
• Alfalfa meal pellets. Slow organic nitrogen that feeds the soil life keeping a lawn thick from below, though alfalfa on lawns comes with a caveat about its own strength.
• Granulated gypsum and kieserite. Calcium and sulphur in granular form, and magnesium for lawns that look pale despite being well fed, which is one of several reasons a lawn turns yellow.
• The lawn kits in Bundles & Kits pair these up for waterlogged and autumn lawns at a little under the sum of the parts.

How to feed through the year

Feed from spring once the grass is actively growing, and again through the season as growth demands. Rates and frequencies are on each product page. Water in after spreading if rain is not forecast. Taper off in late autumn: feeding a lawn hard into winter pushes soft growth at the wrong time of year. Feeding a lawn the organic way works through the seasons in more detail.

When to feed lawn grass in spring

Spring lawn feed put down in February mostly goes to waste: the grass is barely growing, the soil is cold, and nitrogen a lawn cannot use either sits there or leaches. Wait for the soil to warm and growth to start, which for much of the country means mid-March to late April, later in the north and on heavy ground. The first cut is a better signal than the calendar.

Summer

Through summer the limit is usually water, not nutrition. Feeding hard into drought stress asks the grass to grow when it cannot, so raise the mowing height and fix any infiltration problem before reaching for more nitrogen. A liquid feed after rain is the gentler way to restore colour in a hot spell.

Autumn and winter

From September, ease the nitrogen off and switch to the potassium-led autumn programme, keep working on compaction while the ground is still warm enough to respond, and leave the high-nitrogen feed in the shed until spring. The whole autumn set is on the Autumn & Winter Lawn Feed page linked above.

Common questions