Spring renovation involves a series of operations and inputs that are initiated in sequence and complement one another. The success of spring lawn renovation will be dependent on a number of factors, such as the current state of the sward and soil profile, current resources available, notably what machinery / tools you have at your disposal and how much money you want to spend.
The timing of the spring renovation will often be determined by the weather and local conditions. The optimal time will generally be when soil temperatures are rising above seven degrees and air temperatures are in the mid- teens to stimulate some grass growth which is often seen in late March / April depending on what part of the country you live.
The following activities are generally implemented during spring renovations and usually carried out in the following order, moss treatments, mowing the sward, scarification, top dressing, overseeding, fertilising, brushing and watering / Irrigation if required.
Weed control may be dealt with prior to or after spring renovation. Any accumulated moss growth should be dealt with by applying an approved moss killing chemical, wait for it to die, then remove by scarification.
To maximise the effect of a spring renovation it is essential to evaluate the existing condition of the lawn. This can be done by carrying out a series of soil tests to measure soil pH, organic matter content, particle size distribution (PSD), bulk density and soil penetration resistance. Coupled with a visual assessment of how much grass cover and weeds are in the sward, this will help determine the level and extent the spring renovation should take.
A lawn may decline for a number of reasons - lack of cultural practices, drought, weeds, diseases, shade, poor soil, neglect, abuse and over use. Spring renovations helps restore turf health and quality, rejuvenating the soil and sward after winter, thus preparing the surface for the new growing season.
The lawn is usually mowed prior to starting any renovation works. The objective of mowing is to clean and prepare the grass surface. Grass growth in spring can be uneven and varied. Mowing the grass to a uniform height will help prepare an even surface for scarification and top dressing operations.
During growth the grass plant produces a lot of dead material above and below ground level. Scarifying is the term used to remove this unwanted vegetation. There are many different ways and methods of scarifying lawns and turf surfaces. The process usually involves a raking / cutting action to clean out the thatch debris, and can be done manually using spring tine rakes or mechanically using specially designed rotorakes, verticutters and knife action machines.
In recent years we have seen a number of leading mower manufacturers produce a mowing machine that offers a cassette system that includes some scarifying reels that can be used to scarify your lawn. However, these can be expensive, and most people tend to hire in a dedicated scarifier.
Generally you will scarify in two directions and collect and discard the arisings ( dead grass & moss). This is usually followed by carrying out some forking/ aeration work.
Aeration is an important part of the renovation programme. Not only does aeration remedy any compaction problems by restoring and improving air movement in the soil profile, it also provides channels and openings for the top dressing materials to integrate. There are now many choices of aeration equipment on offer to help make the job easier, in most cases it is best to hire a machine to do the job. We should be aiming to penetrate to a depth of between 100mm -200mm with 6-10mm diameter tines.
The application of a good quality top dressing, in combination with a suitable aeration programme will go a long way to restore levels and aid surface drainage.
There are a wide range of materials available for top dressing, ranging from straight sands, clays, loams and local soil materials through to purpose mixed root zones combining clays, loams and sands. These mixes can be tailored to suit the customers needs, and can range from 80/20, 70/30 and 60/40 sand/soil percentage mixes.
The success of top dressing will also be influenced by the amount applied and how well it has been worked into the turf surface. Applying too much dressing will have a detrimental affect, smothering out the turf and increasing the likelihood of disease, slow grass growth and, in some cases, will kill the turf.
To re-establish grass cover , it is necessary to overseed the area with new grass seed. It is not cost effective to use cheap or old grass seed stock, as germination and establishment is likely to be poor. Buy your seed from a reputable company which specialises in developing and marketing quality grass seed mixtures. These seed varieties may be more expensive but they do guarantee quality and performance.
Most seed suppliers will recommend sowing rates but, as a rule of thumb, it will generally be about 35grams of seed per sq/m. Temperatures above 12°C, a moist, well-aerated seedbed, close seed/soil contact are primary requirements for rapid grass seed development. Machinery designed to sow grass seed include disc, direct drilling, oscillating and broadcasting mechanisms. The best results are achieved when the seed has direct contact with the soil, and preferably below the soil surface.
Seed that is left lying on the surface and not in direct contact with soil is prone to drying out and being eaten by birds. Ensure moisture is available for germination.
Prior to applying any fertilisers it is essential to obtain the nutrient and pH status of the soil. This can be achieved by sending soil samples to a soil laboratory which will carry out a nutrient analysis of the sample. Once obtained you will be able to choose a product that offers you the correct N P K fertiliser ratio for your soil.
Many of the leading fertiliser manufacturers offer a balanced spring or re-seeding fertilisers for turf renovation. Something like a spring / summer 9:7:7 NPK product would be ok to use.
Once all top dressings, grass seed and fertiliser materials have been incorporated into/onto the surface, it is important to work the material into the profile by brushing, dragmatting or luting. These operations ensure the materials are worked in evenly, and prevent any excess material remaining on the top. This operation is best done when the surface is dry, enabling the material to distribute itself easily.
To renovate successfully, adequate water must be available from seeding through to completion of germination. Try not to allow newly overseeded areas to dry out once watering has commenced. Initially, maintain a constantly moist seedbed with frequent waterings of short duration. As newly germinated seedlings begin growth, decrease the frequency, and increase the duration of watering to encourage deeper rooting.
Spring renovation is often a time consuming and expensive exercise. Successful spring lawn renovation requires detailed planning and programming, to ensure the right materials and equipment are available and working throughout the renovation process.