Applying fertiliser if no rain is due. This is a very commonly asked questions, also something l have asked myself and get asked often, based on autumn/winter feeding.
First of all, the bag of the product is your number one guide and most say water in within 24 hours if no rain.
But if like a lot of groundspersons/greenkeepers you have packed away your hoses and sprinkler your question maybe is the overnight dew enough to water in the fertiliser?
In general, yes but just a few things to consider below
As long as you’re getting dews this will be enough to start to wash in and break down the fertiliser granular and wash the salts in that are contained within fertilisers.
Allowing the dew to water the fertiliser in may take much more time to break down than if the fertiliser is well watered in by irrigation or rain.
Another consideration of applying fertiliser is if your surface is growing a lot and your cutting regularly, if your granular are still quite big there a risk of crunching them, so fertiliser containing mini granular could be helpful.
Is crushing fertiliser granular a major issue possible not, but if you crush them too early on when they are too small the period the fertiliser is available to feed the plant will be shorter.
Avoid applying fertilisers to a wet leaf as this increases the possibly of scorching the leaf tissue.
Fertiliser containing iron
Considerations if the fertiliser product contains an element of iron (Fe). If the product has not been washed in well and makes contact with a mowers roller, then there is always a chance of burning the grass leaf especially upon turning of the machine, this will appear as leaf blackening.
Iron and fertilisers draw moisture out of the leaf, though less of an issue around damp/cool months such as autumn. It is also advised to apply fertiliser to a dry leaf to help prevent scorch.
Will the grass plant survive yes, but if it’s a very young plant and only at the one leaf stage you could well end up harming it, so avoid fertiliser containing iron around seeding young seed?
Fertiliser pick up during mowing could also be an issue so try and cut at the driest part of the day and once the granular has broken down a bit or at least is off the leaf.
If people are likely to be walking across your surface, then this would be another reason to consider watering in or waiting to apply prior a period of rain.
Also keep an eye on the weather, as dewy evenings can soon be replaced with an unexpected frost, so keep an eye on the forecast. Avoid application of fertilisers around periods of frosts to prevent harm to grass via leaf burn.
If the plant isn’t growing too much and you can give the fertiliser time with the present dew to wash and break down into the soil. The ideal is always to wait for rain and apply prior. If any any doubts get the hoses out and water it in.
Avoid frosts and iron containing product applications around frost windows. For me if l want to get on sooner, l ll water in if l am happy to let the dew break the fertiliser down over a week or so l ll let the dew do its job.
Applying fertiliser if no rain is due by Brian on behalf of the TurfCareBlog community.
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