Autumn Lawn Builder Fertiliser

5.0 (1 reviews)

In Stock

£24.99

A slow-release autumn fertiliser that repairs summer wear, thickens your grass and keeps it green as the temperature drops.

Why It Works

✓One application feeds your lawn for up to 10 weeks
✓Keeps your lawn thick and dark green through autumn
✓Iron free — no orange stains on your patio or driveway
✓Safe for kids and pets when used as directed

Coverage Area:

2.5kg Bag | Covers 70-100m2 8kg Bag | Covers 228-320m2

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Product Overview

iGrow Carpet Autumn Lawn Builder 12-4-12 + 4% MgO + 2% CaO

A slow-release autumn fertiliser that thickens your grass, repairs summer wear and tear, and keeps your lawn green and healthy as the days shorten. Iron free, so no orange staining on paths or drives. Safe for kids and pets when used as directed.

The science bit

The partial coating on this fertiliser pauses nutrient release as soil temperatures cool. Unlike cheaper products that unload everything at once, your lawn gets a steady supply without the late-season growth spurts that invite disease.

Nitrogen (12% N)
Encourages fresh growth, helps grass thicken up and repairs the damage summer leaves behind.

Phosphorus (4% P)
Supports strong root development, improving your lawn's ability to find water and nutrients. Sets up a healthy foundation going into the colder months.

Potassium (12% K)
Strengthens the lawn against stress. Colder nights, foot traffic and disease pressure. Keeps your grass resilient when conditions get tougher.

Magnesium (4% MgO)
Fuels chlorophyll production, giving you a deeper, richer shade of green without the staining you get from cheaper iron-based products.

Calcium (2% CaO)
Improves root strength and soil structure, making it easier for grass to push down deep, strong roots.

Technical Specifications

Total Weight

2.5kg

Coverage

70-100m²

Application Time

September, October and November

Reapplication

10-12 weeks

How To Apply Our Fertiliser

Measure your lawn using our lawn measurement tool
Set your spreader as per its instructions
Use a spreader for even coverage — do not apply by hand
Do not apply in frost
Keep children and pets off the lawn during and after application until watered in and dry
Apply at 30 grams per m² for best results (the product can be applied at between 25-35g per m²)
Blow or brush any product off hard surfaces afterwards
Water in thoroughly for 15 to 20 minutes, or leave if at least 20 minutes of steady rain is forecast within 24-48 hours. The sooner it's watered in, the faster it gets to work

Want to get the best results? Our free Beginners Guide to Fertilising Your Lawn covers everything from spreader settings to professional application techniques.

Q: When should I apply it?

September and October as growth starts to slow.

Q: How much do I need?

Our fertiliser can be applied at 25 to 35 grams per m². We recommend 30 grams per m² as the ideal rate as it gives great results while allowing for a little overlap around edges. Use our lawn measurement tool on the website to calculate exactly how many bags you need based on your lawn size.

Q: How quickly will I see results?

4 to 7 days after it's been watered in.

Q: What's the best way to water it in?

We recommend using a sprinkler as depending on your water pressure, a 15 to 20 minute soak is enough to get the product working. If rainfall is forecast within the next 48 hours that will also do the job, as long as it's not just a light shower.

Q: Will it stain my patio or driveway?

It shouldn't as our granular products are iron free. That said, it's always best to brush or blow any product off hard surfaces before watering in, just to be safe.

Q: How long does it last?

10 weeks in normal conditions. If there's been little rain and slow growth it can stretch to 12 weeks.

Q: Can I use it in winter?

Yes, at a reduced rate of 20g/m² through December to February.

Q: Do I need a spreader?

Yes as a spreader gives you even coverage and prevents patchy results. Hand spreading isn't recommended.

Q: What spreader setting should I use?

This varies by spreader model and walking speed. We have a quick start guide on the learning hub.

Q: Can I apply it in the rain?

Light rain after applying is fine and will help water it in. Avoid applying just before very heavy rain as it can wash the product off the lawn before it has a chance to work.

Q: What if I accidentally over-apply?

Water the area thoroughly straight away to dilute the product and reduce the risk of any scorch.

Q: Is it safe for kids and pets?

Yes, once watered in and dry. Grazing pets like rabbits and guinea pigs should be kept off for two weeks or three cuts, whichever comes first.

Precision Tool

Measure Your Lawn

Use our free interactive tool to measure your lawn's exact square meterage. Get accurate product recommendations and cost estimates based on your lawn size!