Importance of Spring Fertilising

Spring is the most important time of year in the maintenance schedule for any type of grass. What is applied, and just as importantly, when it is applied, will largely dictate the quality of the grass sward for the rest of the year.

Fast Start

Depending on where in Northern Europe you live, the Spring can arrive anywhere from early March, right through to the middle of May, but as a general rule the best way to decide when to apply the first fertiliser will be when the day time temperatures are in the low to mid teens centigrade for more than a few consecutive days. In South West Scotland for instance this normally occurs around the middle of March, where as in the South of England it can be early March.

What To Use

In my experience, and it has now been proven in scientific testing of different fertiliser types, an early Spring application consisting of ten to fourteen per cent nitrogen, along with a high iron content of eight to ten per cent, is by far the most efficient way of boosting early Spring growth.

The analysis to look for on the fertiliser bag will read something like 12.0.0. +10% fe, with recommended application rates also on the label. This will normally be between thirty five to fifty grams per square meter. You normally would not get that type of mix in domestic sales, but easy to get your own. Buy iron, and straight nitrogen, urea is best in Spring, and mix them roughly fifty/fifty, before applying at 35 gram per square meter. Get here.

This nitrogen content gives the required boost to growth in early Spring to quickly fill in any thin areas before weeds can get a chance to colonise, and also quickly take over from the moss killed by the iron.

Summer Fertilising

After the main growth spurt in the Spring has slowed down, the grass does not require nearly as much fuel to keep it healthy. On a well cared for lawn I would be advising a fertiliser containing some nitrogen and some potassium, and depending on the moss content some iron. This would be a good organic fertiliser for Summer use, Green comfort. A wet Summer will produce more moss so will require more iron for instance. The other main nutrient usually found in fertilisers is phosphate, which in my experience has no proven benefit in turf, other than when first sowing out a lawn to aid establishment.

When to Apply

I would normally advise applying a fertiliser twice over the Summer months, one in late May, and the other around mid July. The analysis on the label should be around eight per cent nitrogen and four to six per cent potassium, with two to six per cent iron. But these are nominal figures, get the closest you can.

Liquid or Granular

The easiest way to apply fertiliser is in granular form, but my own preference, and a much more efficient and versatile way is to apply in liquid form using either a knapsack sprayer, find here, or on smaller areas even a watering can.

This gives the opportunity to add some seaweed liquid, or refined manure, which both contain millions of bacteria and fungi to enhance the health of the soil. This helps the soil the make more efficient use of any fertilisers that are applied. More of this in another article. Find liquid fertilisers on our online shop. Or find here.

There is also much less likely hood of scorch damage to the turf by granular fertiliser being applied in dry conditions.


As the weather in Northern Europe in particular can be very fickle, it is important to be flexible in the approach to applying fertiliser, with it being more important to apply in the right weather conditions, than to stick to a rigid timetable that would mean not getting the best out of these applications.


I will be very happy to answer any questions that anyone reading this wishes ask.