A starter fertiliser designed to prepare your soil and give new grass the best possible foundation before seeding or laying turf. Safe for kids and pets when used as directed.
Because it's the same granule size and applied at the same rate as our Spring, Summer and Autumn feeds, there's no guesswork — it fits straight into how you already work.
Applied before sowing or laying turf, the higher phosphorus level drives rapid root development from day one, while nitrogen and potassium support even, healthy growth above and below the surface.
Nitrogen (6% N)
Encourages healthy top growth as new grass emerges.
Phosphorus (9% P)
The key ingredient at this stage. Drives rapid root development so seedlings establish quickly and evenly.
Potassium (6% K)
Strengthens young roots and shoots, building resilience to stress and disease from the start.
How To Apply Our Fertiliser
Want to get the best results? Our free Beginners Guide to Fertilising Your Lawn covers everything from spreader settings to professional application techniques.
Q: Do I apply it before or after seeding?
Either works as before seeding gets nutrients into the soil ready for germination, and after seeding supports early root development.
Q: Can I use it when overseeding an existing lawn?
Yes, it's ideal for overseeding as well as new lawns and turf laying.
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?
4 to 8 weeks, giving new grass the support it needs through the full establishment window.
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.
Seeds doing extremely well well even though we have a mini heatwave going on fertiliser must of helped
That looks Fab, well done!!
Excellent service from start to finish. Coming along nicely. A few patches where the seed hasn’t taken and a few weeds. I’ll soon sort that out with igrowcarpets expertise
Looks smashing! That won't be long filling out
Great service and great products, which arrive within a couple of days. But what is even better is the advice and knowledge on the igrow site. Easy to understand and follow. I’ve had a problem lawn for years and I’m really hoping this year will be different thanks to these guys. This is my lawn at the start of being repaired and reseeded.
Hi Clive, it would be even better if you could update your review after your hard work. I would love to see some before and after pictures.
Thanks for your review!
Great product - thoroughly recommend
Cheers Yick, that's exactly what we like to hear!
Yes I have been using Seaweed Lawn Booster now for several months and Im starting to see the results.
Brilliant product
Does what it says on the tin/bottle
I started following Robbie primarily because the Antrim Coast has very similar weather patterns to the West of Scotland where I'm. I found the majority of similar lawn advisors were based much further South and due to the temperature differentials growing starts earlier and goes on longer.
Having used proprietary brands for >40 years, which I have to say do the job but never seem to quite produce the results I hoped for.
I thought l'd try some of the "iGrow Carpet" products. I purchased the small, enough for me to make a single application, "Summer Power Pack" Having followed Robbie's advice re mowing during the "Heatwave" I was cutting slightly higher twice a week combine that with setting the spreader at half the recommended dose, but doing two passes East to West then South to North. As there was no rain forecast I watered on alternate days and I noticed a difference within a couple of days.
Bottom Line - I am very happy with the initial results.
Loving the product and all the info you’re providing! Slightly obsessed now! Keep up the excellent work. Been recommending you to others.