Ferrous Sulphate Dosage for Killing Moss

I've got two big lawns to de-moss and scarify over the next couple of weeks. One lawn is absolutely massive and tomorrow I'm going to spray ferrous sulphate to kill the moss (mostly the springy type).

I've Googled and Googled to find the right dosage as the 25kg sack the customer bought stupidly has no application instructions. There are so many varying ratios online that I've given up.

If you've sprayed ferrous sulphate in the past and had success in wiping out moss, please can you advise your mixture ratio, preferably by litre. I'm using a 16L knapsack and am incredibly confused at how much FS is needed.

Any help would be greatly appreciated!!!!

 

" Wiping out moss " no chance

I did mine last month and its still going strong in places. I did a coffee cup worth to a 10 litre sprayer. Couldnt risk more in case run off went into pond killing my fish. Grass got real green though.

 

What does the packaging state , ie what is the ingredient list on the packaging.
If it's soluble and is 20% Fe then as a rough guide it would be 2.5 - 5.0 g/m2 with a water volume of 45 - 90ml/m2. You would need to aim at the higher scale to kill of the moss.
This is a knapsack application rate.

 

As Liz said the Fe solution strength you buy is important . The Iron Sulphate you buy at a garden centre will be around 10% Fe . I use a 30%Fe to moss kill my lawns , which I can only find on Ebay.
This is the calc I use to dose my lawns with a coarse watering can rose. Its amazing how quickly the moss blackens . I leave the moss kill for 2 weeks then rake it out . Top dress reseed . Then wait for the moss coming back ! It is a nice shade of green after all
Watering can 9 litres = 12 sq m ( fanning can from side to side = 2 metres walk slowly forward = 6 metres approx )
Sulphate of iron as a moss kill = 4 to 5 gm / sq m
Dosage per watering can 40-50 gm

http://www.ebay.co.uk/itm/IRON-SULP...-Fe-30-/171695779680?var=&hash=item27f9ddaf60

 

Thanks for your replies guys.

The neat product was industrial strength stuff - and required 30g per liter to kill the dreaded springy stuff.

Took a 16 liter knapsack and spent nearly all day weighing, filling buckets, stirring and spraying the moss (admittedly at a slightly higher concentrations). The affected areas turned black within minutes.

A couple of weeks later, it was scarified with a hired Alko 4000VB, which IMO made the job a real mess. It just didn't remove the black moss fully no matter how many times you went over it, or on whichever depth setting.

I rang the hire company and had an exchange of words. They say not to kill the moss beforehand as the scarifier will remove ALL of it, yet if it is not dead, then wouldn't it just be transferred from one area to another?!

I'm having to manually spring tine the remaining stuff and 4 hours of it today nearly put my back in a coma. There is about the same area to do again next week..... oh happy days!!!

 

I agree with the company Mowerman, I wouldn't use a moss killer if I was going to use a scarifier. Moss killer is okay for patches or small lawns but will have to be raked out by hand after. For larger lawns, then let the scarifier do the work. If the lawn isn't completely clear after use then give it a few weeks to recover and then try it again.

When using the scarifier go over the lawn in different directions. First the length, then the width and follow with diagonal if possible.

 

I'm afraid you were up against it. The company is incorrect that you can remove all the moss if not treated, you will remove most of it but not all. The more times you run over the ground the more damage is done if the blades are set incorrect.
The machine to be honest is not really top notch for commercial use, you need to look into scarification to understand blade attachments that are meant for various jobs. You needed a thin blade setup with a higher number of blades which would have helped and you would aim to just touch the surface if simply removing moss. Altering the depth will do nothing but churn the soil with that machine which is why you need to know more about the machines and their setups. Hire companies are as they say, hire companies, they don't know anything about turf management so be warned not to listen too much to their advice which can lead to a disaster, an unhappy customer and you picking up the tab to correct the work.
With a good machine you would remove a lot of the moss but with clients you can't say all will be removed and you need to explain why and how iron deters moss and it's attributes for the grass plant. You also you need to explain why the problem will return in most cases.
You need to see what type of moss it is to see what can be done. As you've discovered running over it multiple times just makes a mess if the blade and machine is not correct. This makes turf recovery harder and even more as you are about to hand rake. A nice even scarification means the grass recovers evenly and does not show patches where sections have been hammered.
It's one reason I don't hire machines as they simply don't cater for all work and if you really want to step up then it's a case of purchasing a machine that is capable of various blade setups so you can tackle different lawns.
You will be there for hours trying to take every last bit out and sometimes it pays to takle moss spring time so that you can work in drier conditions and that the grass can be fed to promote growth and any small amounts of black moss will be soon lifted out with the cuts.
Customers will often have ideas on what they want and how they see the lawn but reality it can take a while for a poor lawn to be put into shape. I think it's the I want a nice lawn instantly kind of problem you see a lot rather than let's take a step back and think how over a season we can form a program to promote the grass and to weaken the moss grip.
I've had customers with really poor lawns willing to pay whatever to have a nice instant lawn and I keep to my word and explain the time scale involved.

 

Thanks very much for your replies.

I've spoken to someone who is somewhat of an expert on scarification and the machine wasn't the right one for the job. If it had a rake attachment, it would've pulled the moss out much better than the machine I hired with the blade setup. He also recommended the use of a moss killer beforehand.

The hire guy wasn't exactly the friendliest of types and he said "under no circumstances adjust the depth setting" as it is set perfectly for removing all of the moss. Yeah right.

Most of the remaining black stuff was raked out by hand (took hours and hours) over a couple of days and the black stuff the was remaining seems to have withered away which I was deeply surprised by.

The garden owner's son commented the other day how well the colour of the lawns looked, so am pleased it turned out alright in the end. There doesn't appear to be live moss anywhere and the ferrous sulphate may not have been the ideal solution but in the end it paid off.