Brown patches on the lawn

By Jim McColl

Published:

LAST Friday, I managed to give our front lawn a cut for the first time. My problem, shared by many, I’m sure, was that under the protection of the hedge it is bright green and growing vigorously while out in the open it is still brownish and showing little sign of budging. Setting the height of cut at what I thought was a reasonable compromise height, I got the job done.

Even so, in the most sheltered strip, I was probably taking off a wee bit too much, but since it is protected I don’t expect any adverse reaction.

I am now on the treadmill – I will cut every week until the end of the season, not even thinking about lowering that cutting height until the end of May or thereby. It is looking tidy and cared for, and that is all I need.

The next job is to scarify lightly – as, indeed, we were doing on Beechgrove last week – then on with the fertiliser.

I did have a question the other day from a chum who has a very sheltered garden. He is worried about patches appearing on his lawn – they start yellowish and end up a brown colour. The patches start quite small, saucer-sized or even less, but seem to grow and join up. What’s up, and what’s to be done?

Almost certainly this is Fusarium Patch disease, a fungus that lives in the soil unnoticed, and quite harmless, until a certain set of conditions come together; then it will become very active and, as a result, cause these patches to appear on the surface. It is seen more often in late autumn, but will also occur in spring.

This is one disease for which we have no chemical control available, but it can be cured by cultural means. You won’t be surprised to learn that the weather is intimately tied up with the set of conditions I referred to earlier.

Firstly, we have had a wet winter and, if the lawn area drains very slowly or if the lawn is seriously compacted, we have the first of the conditions that contribute. Secondly, if the lawn has been covered in snow, which is slow to disappear from the surface, perhaps because the area is shaded from winter sun, we have another contributing factor that helps diagnosis.

Add to that foot traffic on the area when it is covered in snow or hard frost – this may cause physical damage to the sward. And late application of fertiliser in the autumn may have led to a surge of soft growth.

All of these, taken together, create ideal conditions for Fusarium to flourish.

Apply fertiliser – when?

This season, the weather conditions have been extremely trying. Gardeners may be slightly more conscious of this because of the need to get things sown and planted.

This may be a scenario that we have to become used to.

Some of you will have noticed that, at the beginning of the month, we made a bit of a start at Beechgrove, chancing our arm by sowing some early carrots and planting a row of Duke of York tatties.

We were able to do so because we had the ground covered for a week or two beforehand to prevent the soil from becoming wetter and, indeed, hoping that the temperature would rise a bit as a result.

During that period, on good days, the covers were removed and the ground given a light cultivation. Although the conditions could be described as marginal rather than ideal, in a better year, the timing would have been right. In a few weeks, we will be able to see whether the gamble has paid off.

As I have said before, the incentive is based on achieving the longest growing season possible for these particular crops consistent with calling them “early”.

What do you call early? That depends on where you live. Without any further artifice, Dukes planted in early-April should be ready for harvesting in June. That is not to say they are not worth having in August; it simply means that we can enjoy Dukes in June because they have a short growing season – the first home-grown earlies of the year, and they are to be savoured.

As it happens, potato fertiliser is often applied to the drills as the tubers are being planted. In the main, however, the general advice would be to apply a balanced fertiliser to the vegetable plot 10 days before sowing.

At home, I tend to apply it during my final preparations for sowing and planting, incorporating it into the top layer of soil using a border fork or hand cultivator. Because our vegetable garden has been cultivated regularly since we moved in more than 20 years ago, with organic matter being incorporated yearly, I use little fertiliser, almost as an early booster.

My point is that, while organic matter will eventually break down to release plant nutrients, the process is very slow. Granular fertiliser, on the other hand, is assimilated more quickly.

Around the garden, there are many elements that require that same boost, especially where you are not able to incorporate organic material – I mean, of course, shrubs, fruit trees and bushes, hedges and other perennials.

Now is the time to give them a boost using a slow-release organic fertiliser such as pellets of chicken manure or part-organic/part-inorganic Vitax Q4. Follow the instructions on application rates, lightly cultivate into the surface and then, if you have the material to hand, add a mulch.

That, finally, leads me to a comment made by Kate Donald when I went to see her narcissus collection up at Inverasdale. We are often asked when to feed bulbs that have been naturalised in borders. The answer is just as the flowers are going over.

Kate uses a liquid feed that has been formulated for tomatoes and which therefore has a relatively high potash content. Mind you, she also made the comment, which I heartily endorse, that cutting off daffodil leaves as soon as flowering is over is not a very clever idea. Tying bunches into neat little knots using rubber bands is no more acceptable.

Wisely, she commented that the trick is to plant the narcissus behind other herbaceous or woody perennial plants that will break into growth and hide the unsightly daffodil foliage as it gradually dies down naturally.