As we head in to the Autumn it’s a time to reflect on the summer and the effect it had on the grass and the implications .
Normally the late summer highlights the poor state of many lawns following a dry period in September – this year due to the pattern of rain fall over the summer many lawns remained relatively green .
Many of us felt it was a wetter summer than 2020, but in fact the rainfall from June to September was similar to last year, despite that many people have said how difficult it was to keep up with grass cutting due to the wet weather.
In fact August this year we had less rain 40 mm over 3 days than last year last year 129 mm – over 9 days.
Where this year differed and very noticeable in August was the number of over cast days and lack of sun. It was also very calm, no wind to dry anything out and so grass remained damp, similar conditions continued in to September. Consequence of this is far more moss this time of year than usual , already where trees cast a shadow across lawns moss growth is quite rapid , so the first moss control application of the autumn will be much needed.
As we struggled to cut the grass – or cut it where it had not been able to dry off the roller on the mower flattened it rather than cutting , and cutting it short where it had grown long when it was possible checked the growth and left scalped areas which had to grow back and in some cases struggled leaving white straggly looking patches . This weather also benefited the creeping grasses that put out stolon’s and became straggly and now appearing as white patches in lawns where they have been cut back and growth slowed down . These areas are going to need to be scarified hard / cut back and possibly over seeded to improve the grass mix.
We have also seen far more disease on lawns – browning areas which look as if they are dyeing back through lack of moisture . Conditions have been perfect for Fusarium patch , Red Thread and Yellow rust , normally these would not be so noticeable in domestic lawns but with the conditions we have had this year they have exploded. Treatment with fungicides is an option – but expensive.
Weeds that we would not normally see in late August / September have continued to germinate with the moisture in the soil or survived earlier weed killer applications as the leaf was not dry enough to completely absorb the chemical when it was applied.
Speedwell is always a problem in grass and there are different types – but one not normally seen that has established it self in the last few months is “Thyme Leaved Speedwell “ this looks very different to the normal speedwell’s having a soft oval shaped leaf and small light Blue flower, it grows very flat along the surface and spreads by extending stems that then root – current moist weather conditions have been perfect for this. Finding a weedkiller that will control this will certainly be a challenge
Thyme leaved Speedwell
The next few days will see high temperatures, grass is already under stress due to the last few weeks dry weather , so if you can water please do so – your lawn evaporates at least 1/4 an inch of water per week when actively growing and you need to top the soil moisture up BUT DON’T OVER DO IT
As we head into Autumn it is vital that you continue to cut the grass on a regualr basis – and keep it free from fallen leaves . Different species of trees will shed their leaves at different times – Oak being the last as it can often hang on to those leaves until early December, so clearing them up on a regular basis is an ongoing task . Leaves contain lignin which makes them robust – the content in some species is higher and this makes them slower to decompose , and left on the grass they can act as a blanket which smothers the growth and can kill the grass before the leaf has broken down.
We are also likely to see a reduction in ant activity – but worm activity will increase – watch out for those worm casts and brush them off the lawn before cutting , if you don’t walking over them or rolling them with the mower will result in muddy patches which will also suffocate the grass.
Chaffer grubs are also very active now and if you strip away the grass turf under the surface you are likely to find the little white grubs that will chew grass roots . This is Crane Fly time of year – or Daddy Long Legs as they are some times reffered to – they lay the eggs in the lawn that turn in to Leather Jacket .
- The RHS give the following information on Leather jackets
• Leatherjackets have elongate tubular bodies, up to 30mm long, and are greyish brown. They have no legs or obvious head
• Lawns develop patches where the grasses turns yellowish brown and often dies. This can be distinguished from similar effects caused by lawn diseases or adverse growing conditions by lifting the affected turf and finding leatherjackets in the surface layers of the soil
• Leatherjackets may also be revealed in lawns by soaking with water and covering with material impervious to light, such as black polythene. The following day if leatherjackets are the problem, large numbers of grubs should be found on the lawn surface under the cover
• Crows, magpies, rooks and starlings will search for leatherjackets in turf. These birds leave small round holes in the turf where they have inserted their beaks.
In addition to bird activity – the biggest pest we can face is Badgers who also look to feed on chaffer grubs and leather jacket . As a protected species we can not do very much to them – the only defence is to manage the lawn to deter the pest and to ensure that badgers can not easily access your garden. Easier said than done, it is remarkable how many there are in Hertfordshire , you might think you are not going to see them on a residential estate, but many new homes are being built on what was once open countryside , and Hertfordshire is actually still quite a rural county with pockets of woodland and open spaces.
Some people have had success with putting chilli powder down to deter them – and male urine , but not sure if that is fact based or just gossip.
I generally don’t like to repeat what I have said before , but comparing the weather this year with last its not so different from a rain fall point of view, and we had that very cold May and not the heat we experienced last May .
The release of the UN report on global warming released yesterday and the fires being reported in Greece and the USA demonstrate how real it is as is the periods of sun that we experience and the sudden torrential down pours that occur.
For lawns these conditions present a real challenge – watering grass is not always an option, and getting rid of excess water just as bad – soil health and structure is the best strategy to deal with this.
Its been interesting looking at the soil profile of lawns that are dying back – the dark patches seen on the surface where grass is suffering are so dry penetrating with a soil auger is a real challenge . The core extracted is often completely bone dry to the point of nearly being dust, and at the surface 2-3 centimetres is a thick layer of dead matted material that acts as a surface sponge when it rains – but prevents water getting through.
You can soon see if your lawn is suffering – if you leave foot prints on it when you walk across it and it seems spongy you probably have a build up of thatch, or moss ( or maybe you have it get to long, a comment regarding that in the final paragraph )
Hence the summer Bio feed we apply , which I have described as a spa day for your grass adds vital amino acids to help the grass recover from stress , and we add a vitamin tablet full of fungi and bacteria which help the soil recover and stimulate consumption of this thatch and turn it back into waste that the grass can feed on.
Lawns that remain looking green and lush now are those that have the benefit of a good healthy soil and open structure – likely to be those that are relatively new where the soil was cultivated to a good depth and roots have been able to go down and soil capacity for holding moisture is good.
Healthy soils are vital to support grass – they need a lot of beneficial bacteria and fungi to be supporting the soil micro- organisms, good soil structure is important to this and extreme weather conditions wet or hot always highlight the problems.
Scarification and aeration is so important in these circumstance – although both can be very aggressive and so need to be done under the right conditions.
Aeration punches holes into the soil , to allow water to get through and oxygen which will encourage root growth. There are different types of aerator tines – some will slit the surface , others will spike or take a core of soil out . Soil type will determine the best tine for the job – it should not be carried out on soils when too wet, ideally it is done when soils are dry , this can have the added benefit of shattering encouraging further cracks to appear in the soil around the tine . However aeration cannot be carried out when very dry – as the machinery will be unable to penetrate the soil as is the case now .
Now is the time to carry out work to improve soil structure – and through September , please don’t hesitate to call for a survey to look at the soil structure of your lawn.
One final point to mention – remember to keep your grass 2 inches long , it can be a bit shorter for fine grasses . When ever you cut grass aim to remove no more than a third of the length – and if you need to reduce the height , try to do it gradually . Also make a point of cutting grass in different directions, every time you go over the lawn the roller flattens it and it actually ends up getting longer which is why you should alternate cuts. Unfortunately with the weather or holidays you might get behind with the grass cutting – when it is cut back hard you are likely to see brown patches where all the top growth has been removed , it will recover once the light gets to it , but if that happens and you then go into a dry period you will need to water to help it along.
Well weather continues to be unpredictable , who would have thought that we would go through June with 2 inches of rain . This provided ideal conditions for newly sown lawns to thicken up nicely and also take the chance to re-seed some at the end of June in the hope that it would stay moist enough to enable germination . Well July has started with showers so you never know what you can get away with .
Even seeing some moss re-emerge on lawns where it had not quite cleared away from earlier iron applications to control it as the rain and warmth provide ideal conditions for re-growth.
Lot of fungi appearing in lawns this is due to warm weather in first half of June followed by wet weather and humidity – nothing to worry about , not harmful and will disappear as soon as it drys out.
Also seeing a lot of Red Thread – particularly on Fescue lawns , again common under the current weather conditions , the grass will grow out of it and only in really sever conditions is it worth treating with a fungicide , and it should really be as part of a planned approach where problems are know to exist
As we move in to July the expectation is that warmer dry weather will slow the release of fertiliser down, so we switch to using an Organic foliar feed to keep grass growing and looking nice and Green
We use a Symbio product made from condensed molasses soluble by amino acid fermentation. Amino acids are the building blocks of protein and improve plant metabolism , sugars act as a bio stimulant for bacteria and the organic content acts as a fungal stimulant . Added to this is a Bio Tab, this benefits the soil micro-organisms , increases root mass, and converts thatch to humus improving water and nutrient retention.
In an ideal world this would be applied after aeration as it has a better chance of getting to where it is needed . Aeration reduces surface compaction and allow air and nutrients in to the soil which stimulates root growth. Aeration can be with hollow tine , in which case it is normal to top dress afterwards normally carried out early spring or autumn or solid tine that can be carried out all year round.
Better late than never – well so much going on in such a short space of time.
May proved to be a cold month , but a wet month , remarkably it provided a great opportunity to re-seed lawns , and most came through looking pretty good , although some towards the end of May struggled a little when after one very wet Monday , the soil rapidly dried out at the surface capped making it tough on any seeds that were just pushing through the surface.
June till now has been generally warm , and lawns were starting to suffer again as they dried out so todays rains have been welcome. Its ironic that today I received a delivery of a compost additive that absorbs water and helps seeds to germinate – wont be needing that for a week.
Ants have been running wild this June and I advise trying to rake the mounds they create in the first instance , this levels the soil out that they heap up and uncovers the grass so that is wont die back. If you don’t do this you will find the mower scalping these high points and leaving you bare patches. You can also try pouring cold water over the patch as ants are not supposed to like a bath , and then dust with an ant powder .
Many lawns have seen clover and trefoil spread this spring , the cold weather earlier on did not deter them and the dry weather suited them as they have a tap root and were able to grow away with out competition from the grass that struggled to make any growth. Both these weeds have relatively small waxy leaf area so when the weed killer is applied it struggles to stick to the surface , and as they are systemic we need the contact to allow absorption .
Weed grasses have also sprung up this year again due to the earlier colder weather – many people have observed when looking down on their lawn from the bedroom window the green patches which seem to appear over night . At ground level it is not so noticeable , these weed grasses get into the lawns from wind dispersal , bird droppings , and may be were already in the soil. There growth habit tends to be horizontal rather than vertical , and when cutting the lawn you can end up just pushing them over which allows them to spread as some will send out roots from the leaf stems. Its worth trying to rake any patches you have before cutting the grass so at least they are standing up to start with.
As well as the straggling weed grass we also have the Poa annua – annual meadow grass , seems to have the ability to grow any where , including the pavements and no matter at what height you cut it it manages to produce flower heads and seed .
One positive it that as we head towards the longest day of the year, and back into shorter days grasses will stop trying to seed and revert back to vegetive growth.
Worst case scenario is to kill the patches off with a total weed killer and re-seed , or to even kill the whole lawn off and to start again. It is unfortunate how these unwanted grasses can change the overall appearance of the lawn – at least if you re-seed , providing everything is killed off before you start you can be sure the new lawn will be from the seed in the pack.