Question: Can I use old, wet lawn fertiliser?

I received this question from a reader in May 2019 regarding using discounted lawn feed. They write:

Hi Kris, I hope you can help.

I inherited a big garden with a very old lawn (30 years at least). I like to keep it in beautiful condition.

Last year (2018) it suffered badly with the hot weather. It is now getting better though looks pretty bad with areas of masses of moss, dried bits and compaction. I bought a spreader and a big bag of J.A. Bower’s feed, weed and moss killer.

My question is this. I measured up and walked up and down with my spreader only to discover the feed is so wet that none was getting out. The lawn the spreader was just mixing it like cement.

The shop closed down a week after I bought the bag but it was expensive.

I’m sure it will do the job well. My question now is, is the bag of feed usable at all? They had them all outside piled up so I expect they were all wet.

Can I dry it out? Is there anything I can do to save it? Should I just go and buy a new bag and cut my losses?

Thank you.

Shana

Hi Shana,

Thanks for your question. Sometimes a bargain doesn’t turn out to be such a great deal as you first though.

Granulated lawn fertiliser contains elements and nutrients either bound together or encased in a water soluble material. Upon contact with water this bind dissolves, allowing the fertiliser elements to disperse into the soil. This enables the fertiliser to be spread easily, but when washed into the soil it can be absorbed by plants.

Can you spread wet lawn fertiliser?

Unfortunately, if the fertiliser is exposed to water before it is able to be spread, it breaks down, as you have found. The result is a gooey mess, a bit like cement, which holds onto water and becomes completely unmanageable. It cannot be spread in a traditional spreader.

Also, if the wet lawn fertiliser has been exposed to the air for a long time, the nitrogen and other naturally gaseous elements will “gas out”. This is when they revert to their original state and dissipate to the atmosphere. This reduces the effectiveness of the remaining lawn feed.

So what can you do with wet lawn fertiliser?

If your wet lawn fertiliser does not contain any herbicides or moss control, you could try to dry out small amounts of it for use elsewhere in your garden. Spread some out on a tray and leave it in a greenhouse. Handfuls can then be used to help feed shrubs or other large plants around the garden. However, DO NOT do this if your product is a “weed and feed” or an “all-in-one” type lawn product. These will contain herbicides or moss control products which may harm other plants. Herbicides used incorrectly can cause problems.

You can try to mix your wet lawn fertiliser with dry horticultural sand or granulated limestone. This will help to break up the wet lawn fertiliser clump and it may even become spreadable. If it still won’t go through your spreader, distribute it over your lawn by hand. Be sure to wear suitable gloves when handling any lawn care products.

Dissolve in water?

You could try to see if your wet lawn fertiliser dissolves in water. Fill a watering can with warm water and mix in a cupful of your lawn feed. mix it through and see if it dissolves. You can then sprinkle this on your lawn through a coarse watering can nozzle. Make sure you rinse the container afterwards thoroughly afterwards.

Disposal of wet lawn fertiliser

If you decide that neither of these methods work, then you should safely dispose of it through your local council recycling facility. Contact them directly for advice.

Combination lawn weed and feed products contain herbicides which can be harmful to the environment if disposed of incorrectly. Always follow local recycling guidelines.

Thanks again for your question, I hope this is useful.

Kris Lord

Main article photo is a stock image and was not supplied by questioner.