A controlled-release summer fertiliser that keeps your lawn thick, dark green and growing steadily through the warmest months. Iron free, so no orange staining on paths or drives. Safe for kids and pets when used as directed.
Nitrogen (15% N)
Powers steady, lush green growth through summer. Drives photosynthesis and keeps your lawn looking its best when it's under the most pressure.
Phosphorus (0% P)
Deliberately excluded. Phosphorus moves slowly through soil and isn't needed by established grass in summer. We've left it out and focused on what your lawn actually uses.
Potassium (10% K)
Helps your lawn hold moisture during dry spells and recover quickly from drought stress, keeping colour vibrant for longer.
Magnesium (2% MgO)
Fuels chlorophyll production, giving you a deeper, richer shade of green without the staining you get from cheaper iron-based products.
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: When should I apply it?
June to August. Avoid applying during a heatwave or drought as you should wait for a cooler spell or before rain.
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 it burn my lawn in hot weather?
Not when used as directed. Water it in within 48 hours of applying.
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: Can I apply it to a newly seeded lawn?
Yes, but also check out our Pre-Seeder which is specifically designed to give new seed the best possible start.
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.
Loving the product and all the info you’re providing! Slightly obsessed now! Keep up the excellent work. Been recommending you to others.
Hi Jonty, that's what we are here for! Lawn looks great too!
Very straightforward to use and with the desired results. The YouTube video series was excellent at explaining the best was to approach the job of spreading such fertiliser and being new to the lawn care scene they were much appreciated.
We built that video into a full course, its on the learning hub. Once you learn how to do it properly, it makes such a difference to your lawn!
Worked quickly and well
Hi Richard, thank you for your review.
Really looking forward to using it, got to calibrate my Einhall spreader that I bought from one of your other videos. I’ll come back to you in the near future. Thank you. Alan.
Hi Alan, thank you for your kind words! We're glad you're excited to try the Summer Advance Fertiliser. Looking forward to hearing how it goes with your Einhall spreader spreader. We use ours all the time!
Great stuff from Robbie and Jason 😀
Ha! cheers Jason, much appreciated. Glad you're getting on well with the Summer Advance.
I have delays my annual renovations because it has been so dry and hot. I opted to go for this fertiliser instead of the spring version as this is summer weather. I was lucky in that it rained for three days after putting this down. Excellent product and you can definitely see where I missed areas. One obvious point - make sure you set your spreader up properly as the grains are pretty small and it would be easy to blast through a bag and overdose. Excellent product and will buy again.
Hi Anthony
Thanks for the review!
Good shout on the spreader settings, getting that calibration right is key for perfect stripes/
Since you mentioned missing a few spots, you might want to check out our free lawn feeding course on our website. It has a breakdown on how to get perfectly even coverage so you don't get those missed stripes next time.
Thanks again for the support!
It's great stuff 100% recommended
Worked like a dream. Went away for two weeks & came back to very brown patches of grass. Mowed high, fertilised & watered after. One week later the grass is nearly back to normal. Very lush & very green.
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.