How to use liquid lawn food

How to Use Liquid Lawn Food

Liquid feeding of the lawn is suitable from late spring to early autumn during the main growth period in warmer weather.

Liquid feeding of the lawn is suitable from late spring to early autumn during the main growth period in warmer weather. This means the grass will react and green very quickly with the addition of nutrients.

The following is applicable to Lawnsmith Soluble Lawn Fertiliser and may not be compatible with other soluble or liquid lawn feeds.

Liquid Fertilisers are Absorbed through the Grass Leaves

This is more like having an injection so the reaction to the feed is very quick: days rather than a week or two and therefore ideal if you need a quick response.

This also means that if the grass is stressed due to lack of moisture it can be damaged quite easily. The water you spray the fertiliser in evaporates quickly and doesn’t go into the grass whilst the fertiliser, being a salt, dries the leaves rapidly. So, do not use if the soil is dry.

What does Liquid Feed do?

An application of liquid feed is usually about a quarter of the strength of a granular feed. It should therefore be considered as a snack for the grass rather than a main feed and should feed for 4-6 weeks. In addition, it mainly produces leaf growth and not root growth which is why it is a fertiliser for the warmer growing season.

Using Liquid Feed like a Professional

Because liquid fertiliser is quick to react and is not often slow release it will keep your lawn well nourished for just a few weeks. This means it is a great top-up between main granular feeds when you feel the lawn needs a little pick-me-up. Some people will switch to liquid feeding every 4 weeks right through the summer and switch back to granular in the autumn.

When to Apply Liquid Lawn Fertiliser

  • Between May and August
  • When your main feed has run its course and the grass needs a boost
  • When there is moisture in the soil
  • Do not apply in direct sunlight; the evenings are best
  • Immediately after mowing 
  • Between granular feeds to 'grow out' the red thread fungus

Do not use Liquid Products if the Lawn is Dry

There is a popular misconception that liquid products are less likely to burn the lawn than granular products because they are mixed with water. This is true until summer arrives and there is little moisture in the soil. This means that if you apply a salty solution to already stressed grass leaves you'll more than likely cause serious damage. So, check there is moisture in the soil and the grass is growing well before applying. If not water deeply or wait for rain before applying.

In addition, do not water the fertiliser in or water after application. All you are doing is washing fertiliser off the leaves into the soil. If you do that you may as well apply a dry granular feed.

How to Tell if the Grass needs a Boost

When you initially apply any fertiliser to a lawn it will use what it can quickly depending on how hungry the grass is. This means two lawns treated with the same fertiliser can react differently with the hungry lawn gobbling up the feed and greening and growing rapidly whilst the well nourished lawn uses less initially and has less of a growth surge. Using slow-release fertilisers helps reduce the initial surge quite considerably but hungry lawns will always surge.

So, once this surge is over the grass basically has eaten its fill and the grass growth slows. The dark green starts fading a little. This is perhaps the perfect state you want you lawn to be in; fit, growing well, nicely green without being too lush. Over feeding will make the lawn more susceptible to disease.

So, a couple of weeks after that, perhaps a total of 6 weeks after using one of our slow release fertilisers in spring the grass will be hungry enough for a top up. For this you need a liquid feed as it gets taken into the plant via the leaves creating a more rapid but gentle greening without too much growth increase. You can repeat this several times throughout the summer with each liquid feed being about 4 weeks apart until the granular feed in autumn. Liquid fertilisers are no substitute for spring or autumn granular feeds.

The better the growing conditions the more the lawn will eat up your soluble feed. This means warm weather with enough rain is ideal for this feeding regime. If however, growth slows, the grass doesn't spring back quite so much when walked on and it's been hot or dry check moisture in the soil before adding any further chemicals to the lawn.

Warning: Do not apply to grass less than 3 months old. The leaves are very tender.

Can I do the same with Ferrous Sulphate?

To a degree yes. Ferrous sulphate though classified as either a moss killer or fertiliser is in fact just an iron salt. It is the equivalent of a vitamin to you and me and is the reason you may eat spinach because it contains a lot of iron in the green leaves. The more iron the greener it gets, so introducing iron into the lawn greens it up but does not feed or promote growth. If you want to really green up your lawn then mix ferrous sulphate with liquid fertiliser!

Can I mix Liquid Fertiliser with other Products?

You can mix our Soluble Lawn Feed with our Green-up Ferrous Sulphate. Use at a ratio of 4 or 5 parts Soluble Fertiliser to 1 part Ferrous Sulphate. This gives an excellent green-up in a very short space of time.

You can also mix it with either of our weed killers and kill two jobs with one spray. Just add the usual amount of each product to your mix following our dilution rates on the labels.

Do not mix all three together please!