The weather is starting to be fairly consistent so it’s time to continue to focus on getting the lawn ready for its spring renovation. This weekend saw the ground work for next weekend’s final renovation to take place – i.e. seeding, topdressing and working in the topdressing (weather permitting).
Saturday 8th April saw the lawn cut at 40mm (with only about 1/5th – 1/6th of a box of clippings being removed), to prepare it for some other renovation work – hand raking (scarification) and a start being made on forking on the top quarter of the lawn.
As usual the data I recorded was as follows:
- Grass height before cutting: most at 50mm, some up to 70mm;
- Soil moisture reading: 6.2 (waiting 60 seconds to take the reading);
- A fairly heavy surface dew was present on the lawn;
- Air temperature in shade: 0900 = 9.2C; 1500 = 14.7C; 1900 = 12.2C;
- Soil temperature at 50mm depth (taken in shade): 0900 = 6.8C; 1500 = 11.3C; 1900 = 13.2C;
- Relative humidity: 0900 = 91.5%; 1500 = 31.5%; 1900 = 67.7%.
I concentrated on the top area of the lawn which has a fair amount of moss present. Raking is quite a tiring activity if you do it vigorously, but an intense, up to, 5-minute session will start to remove a good amount of moss and surface debris.
Scarification: The technical term for raking. This is the use of fine tines to scratch the surface or to go deeper within the surface layer to penetrate the underlying soil. The aim of this activity is to remove surface debris (e.g. dying stems, dead leaves, moss) and sub-surface debris (called thatch) to help keep the surface more open, improving air flow, reducing relative humidity around the base of grass plants and generally making conditions for a grass plant that much more suitable for good development.
Scarification is also: (i) a physical way of reducing and controlling weeds (e.g. white clover, speedwell, pearlwort) and weed grasses (annual meadow grass and Yorkshire fog in particular); (ii) used to help prepare ground for overseeding; (iii) used prior to fertiliser application to help the dissolved nutrients more quickly penetrate into the soil, and (iv) used to help prepare ground to ‘key’ any applied top-dressing to the existing soil.
I then gave part of the lawn a hand forking: This is the best task you can do to a lawn after mowing, but it can be tedious and relatively slow to cover an entire lawn so certainly consider breaking it down into small chunks aiming to cover entire the lawn in 7 – 10 days maybe.
I used a border fork rather than a garden or digging fork because it is smaller, lighter and does the job perfectly. I made the spacing about 75mm and slightly levered back and forth, not too much though, to potentially help created some fissuring within the soil.
Aeration: The technical term for forking. This process helps to encourage the exchange of soil air with the outside atmospheric air. This activity either physically penetrates the soil with tines (solid, slit, chisel, hollow, and other types of tine) or through the injection of compressed air; compressed water is also sometimes used as a means of aeration with very specialist equipment.
Aeration of lawns will typically be through the use of solid-tines or hollow-tines. Solid tines are good for penetrating soils, although they shouldn’t be used when the soil is wet or too moist as the tines will just smear the soil and will do little to help in the exchange of soil air with surface air. Hollow-tines are good for what is termed soil exchange, reducing heavily compacted soil, or for reducing the thatch content of any lawn. If the soil isn’t dry enough then the hollow tines will not be able to eject the soil cores, which is the whole point of using these types of tines.
Aeration is an essential activity and should be carried out regularly, especially where the soil is compacted, which is typically the result of people or machines regularly going over the same area. Keeping the soil relatively open and well aerated will help to encourage good root growth and will help to create a good lawn surface that is harder wearing and will also be in a stronger position to withstand dry summer or drought conditions.
I also tried a specialist fork, called a hollow-tine fork, which helps remove compacted (or undesirable soil) and can help improve drainage if sand is then worked back into the exposed hole. Unfortunately the soil was still a little moist for this to work effectively; whilst the holes were made the soil didn’t allow any cores to be removed, so in effect the hollow-tine fork was just acting as a normal solid tine fork.
Chris Gray, 9th April 2017