All you need to know about top-dressing

April's Topical question

The Pitchcare Technical Merit award in association with Tillers Turf is now in it's fourth month and we have been inundated with entries each month, the best answers for the topical question in April have been sent off to our panel of judges. So here is a selection of member answers to the question.

Each month we offer a series of multiple choice questions and one topical answer. The competition, devised by Tim Fell (managing Director of Tillers Turf), is designed to help everybody learn a little more in and informal way. It's fun and easy to complete the multi-choice questions, and for each correct answer, your name goes into the hat for the monthly prizes on offer.

The Topical question requires a bit more thought, but we're not giving away a £2000 all inclusive holiday for a one sentence answer! If you read some of the responses below and from previous months questions you'll see what we mean. By the way, these answers are not listed in any particular order, and their technical content is not necessarily correct in all instances, they are published as sent in, with spelling and typo's corrected only.

The best answer to the topical answer each month, as chosen by the judges, goes into the hat for the grand prize.

So click onto the Technical Merit Award banner or link in the menu bar and have a go for yourself.

April Topical Question:

Before, during and after a seasons play, top dressing may be applied to a playing surface. Please explain the reasons as to when, how much and why, you would apply top dressing to your particular playing surface (s).

Best Answers:

1) Although not directly involved with the pitchcare industry, I have just visited Hunstanton Golf Club to write an article on the top dressing regime at 'The Augusta of the UK'. This, hopefully, answers the question above.

The Hunstanton Golf Club, established in 1891, is an 18-hole championship course situated on the north Norfolk coast. It is a traditional links course measuring 6,600 yards off the championship tees and is renowned for its superb, lightning fast greens, which have been quoted in Golf World as being 'as fast as Augusta'.

Head Greenkeeper, Jim Read, is proud of his greens; they average 11 to 11.5 on a Stimp meter, and the fact that the club is one of the UK's top 100 golf courses. Jim has been with the club for 26 years, 24 of them in his current position, having originally been employed on a two-week ditch digging contract back in 1977. "They just kept finding more and more things for me to do", he said. His son, Peter is the Assistant Head Greenkeeper and he manages a total of six greenkeeping staff including a mechanic.

To maintain the speed on the greens, Jim cuts to 2mm, but in recent years has witnessed a severe stressing of the grass around August and September resulting in the onset of anthracnose. This can devastate a green overnight so he has devised a remedy, which he believes will resolve this awkward problem.

Cutting to 2mm has resulted in a root zone that is too shallow to allow the grass to stand up, so after consultations with his local turf maintenance dealer, Norwich based Bartram Mowers, it was decided to increase the depth of the root zone by applying a light top dressing of sand, every week throughout the season.

The aim of this top dressing regime is to raise the height of the root zone and eventually raise the height of cut to 2.5 or 3mm, while still maintaining the speed on the greens.

The theory sounds simple, but in practice hundreds of tons of sand have to be applied to the greens, with minimum disruption to the members and visitors. The solution was to use a trailed top dresser, in this instance a Turfco WideSpin, supplied by Ransomes Jacobsen, the Ipswich based turf maintenance equipment manufacturer.

Jim commented, "The Turfco WideSpin is ideal for fast and light top dressing applications. It has a large hopper that can be quickly filled using a front-end loader and a hydraulically driven conveyor belt and twin spinners gives a uniform application at any speed, with the spinner angle easily adjustable for maximum penetration. The distribution pattern is variable from 15 -30 feet, which means most of the greens can be covered in just two passes.

"In fact, we can top dress all 18 greens and the practice green in just a couple of hours, using 3-4 hopper loads of sand. Previously it took six men all day, and sometimes with a bit of overtime. We used to top dress only four times a year, now we apply a light dressing every week. The WideSpin can lay down a very fine dressing; just a light dusting that in no way interferes with the golfers who are playing on the course. They are probably unaware that the greens have been dressed. One tip I can pass on is that I always put a few handfuls of Bent grass seed in the hopper before we dress; it certainly has proved beneficial here."

Initially Jim thought he would have to buy in kiln-dried sand, but the day of the demonstration proved him wrong. Eddie Jack of Bartram Mowers and Ian Mitchell of Ransomes Jacobsen left their Norwich base in a fine drizzle and by the time they reached Hunstanton they were in a heavy rainstorm, which lasted the rest of the day. The WideSpin coped admirably, in fact, so well that Jim has saved around £3,000 on sand this year it is freely available on site.

"All we do is dig a hole in a secluded part of the estate, remove the sand, transport it back to our shed, riddle out any stones or larger material and then we ready to put it on the greens. I used 60 -80 tons last year, I'll be using around 150 tons this season", he said.

His regime began early in March and is scheduled to continue right through to October. The greens will continue to be cut every day and scarified twice a week and I look forward to returning in September to take core samples to see if Jim has achieved his goal. Watch this space.

2) You would apply topdressing as needed in accordance with the growth rate of thatch on your particular sports surface. You would also consider the quality of the surface levels. If your surface were relatively uneven you would apply topdressing more frequently than someone whose surface is truer. The best times to apply topdressing are when the plants in the sward are actively growing. Applying topdressing to dormant plants runs the risk of suffocating plant parts and lowering the quality of the grass surface.

Disease outbreaks are encouraged by topdressing in warmer conditions because once the application has been made, a microclimate is formed. Before the grounds person has worked it in, pathogens can germinate. Pathogens germinate within a one half-degree range of their ideal temperature so topdressing during the season can be dangerous as well as beneficial. The grass type will also dictate the frequency of topdressing. Creeping bentgrass requires regular light topdressing whereas a tufted Fescue will cope with lower application frequencies.

How much you would apply will be dependent on what you are trying to achieve. You would put on more to fill the holes created by a hollow-coring operation than if you were simply trying to encourage new growth. The spring topdressing may require higher amounts because of the degradation from wind and rain over the winter months. The summer and autumn amounts would be less because they adding to the initial spring amounts.

There are many reasons why you would apply topdressing.

• To increase surface levels.
• To stimulate new root and shoot growth.
• To cover seed allowing it to make contact with soil and therefore providing insulation and maximising the germination rate.
• To increase the water holding capacity of the soil and reducing the amount of water stress during the summer months.
• To increase soil structure by adding a medium that will improve infiltration rates, soil strength, saturated hydraulic conductivity, aeration capacity, nutrient retention, and fertility levels within the soil.
• To allow a soil exchange to take place working in conjunction with hollow-coring to remove a lower quality soil and replace with a fresh, active medium.
• Topdressing with a soil/compost mix has been found to reduce disease instances. Topdressing with an organic substance will increase the microbial populations that attack pathogenic fungi.
• Topdressing also raises the quality of growing medium for grass roots, which increases plant visual and functional qualities such as density, uniformity, colour, texture and so on.
• Topdressing also provides a habitat for micro-organisms within the thatch layer and helps to maximise the thatch layer's decomposition rates.
• Finally topdressing also helps to reduce dry patch from forming within turf. Diluting the sticky mucilaginous residues within the thatch layer improves the water absorbency properties and reduces the hydrophobic nature of thatch.

3) WHEN.

Only when grass growth is strong enough to allow recovery from the covering and associated mechanical operations e.g. scarifying
when surface hollows require to be bought back to true levels
after tyning especially hollow tyning and also after overseeding
before major competitions making sure of sufficient recovery time before the event

HOW MUCH

sufficient to fill the base of the turf without smothering. The grass tips should be visible after levelling or drag matting

WHY

to regain surface true
to stimulate growth through the addition of fresh minerals and organic matter
to modify soil structure when used in conjunction with tining
to assist in the prevention of thatch build up when done in conjunction of scarifying/verticutting

4) Grass hockey:
Middle to late summer, application of a soil sand mix with grass seed incorporated to level any green (hollow spots) noticed during the close mowing of cricket outfields, this has the benefit of a more consistently level surface for what is an aggressive, fast grass sport. Amounts are determined by the level of 'green' areas.

During season, coupled with divotting, to maintain level surface and grass sward repair on high wear areas, I e goal mouths, short and long corner areas, 70-80% soil, 20-30% sand mix.
A top-dressing of straight sand to be applied overall to help drainage and maintain levels during a season of medium to high rainfall, backed up with regular aeration, approximately 10 tonnes in severe weather, which takes into account the transportation of soil from the area on player's boots!

After season: Pre-seeder application a couple of weeks before over seeding, in our case over seeding is carried out using a Gannon gill unit, the spiked rollers are set to scuff up the surface for the seed, I then chain harrow the area and leave for the rain to wash the seed in, followed up with mowing without collecting to give the seed extra cover whilst germination occurs.
I would then like to sit back and watch it grow! Some chance!

5) Before planning any topdressing applications it is vital for the turfgrass manager to consider:

Topdressing has many functions, such as, restoring surface levels, increasing green speeds, protecting the crown of the grass plant, providing a source of nutrition, and correcting soil problems.

The timing of application has an effect on the desired result. Topdressing of cricket wickets to restore surface levels can be carried out from the moment the wicket comes out of play until about the end of January. If topdressing is carried out too close to the start of the cricket season the topdressing may not be 'absorbed' by the wickets and cause them to be dusty later on in the season.

Light topdressing during post match renovation of about 25-50Kg of loam may reduce the need to heavily top dress cricket wickets at all. If however, surface levels need to be improved more topdressing is required after spiking the surface, 200Kg and above will be needed.

A great way of applying topdressing to cricket/ tennis surfaces was seen at Wimbledon lawn tennis club last year. Heavy scarification of the surface was carried out prior to re-seeding followed by light topdressing. Once the turf had established more topdressing was added to restore surface levels. The reason for this was that a thick blanket of soil did not smother the germinating seed, and levelling could be carried out without smothering desirable grass.

Hollow coring and topdressing can be carried out to remedy problems with wickets, such as low bounce. Soil exchange maybe the only option on wickets that cannot be taken out of play. This process however takes time; it could take up to 10 years to see an improvement in bounce, and may lead to inconsistent wickets during the process.

Topdressing winter games pitches are generally carried after the playing season finishes to restore surface levels and improve surface drainage. Sand banded pitches will need to be top dressed to keep the tops of the slits open. If spiking has been carried out prior to topdressing to improve surface drainage then about 60-100 tonnes of topdressing will be needed per pitch. If however, the surface is due to have cricket played on it spiking should be avoided as it may cause cracking, and light topdressing of 20-40 tonnes should be added to improve levels.

It is worth mentioning that applications of sand to a heavy silty clay loam will not immediately alter the soils texture. It would take years of heavy applications to change the soil texture to a sandy silt loam.


Light frequent dressings of compatible material is ideally suited to surfaces such as golf greens or bowling greens to maintain surface levels and green speeds.
Topdressing golf greens and fine turf can be carried out at any time of the growing season, provided that the turf can recover. Topdressing too late in the season could smother the turfgrass plant, leading to diseases such as fusarium!

The sand used in greenside bunkers should be compatible with the root zone of the green. Problems with the root zone can arise over time if unsuitable sand is used just because it looks better.

Main points:

Topdressing should be carried out only when the sward has time to recover

Spiking should always be carried out before topdressing to incorporate the soils together, but if light dressings of similar material are used spiking is not always necessary.

The reason for topdressing should be apparent before the topdressing procedure is carried out. A suitable material sourced, and a storage area decided in case of bad weather.

6) What is top dressing- a dressing that is applied to a surface or area, to improve its performance, it could be sand, soil, a mixture of the two, or peat, manure, leaf mould, compost.
Applying top dressing has the following benefits: improves the roll of the ball (golf mainly), can "sweeten " the soil, improves the levels, can aid either natural drainage, or enhance drainage systems with the application of suitable particle size materials can be part of a soil exchange maintenance programme, vital to seed germination, by ensuring soil-seed contact, can help stabilise sports surfaces, can compliment a fertiliser programme by ensuring the dressings that are being applied are exactly right for your own unique situation.

When to apply top dressing?
Generally on most sports pitches top dressing is applied at the end of the playing season, whenever this may be, the exception to this is golf, where it tends to be applied at monthly intervals, however, the difference in quantity tends to be minimal, as golf greens take a "dust dressing " regularly, other pitches will receive a "blanket dressing" once or twice a year, the timing of top dressing has to be carefully planned so as not to affect the germination of grass, the sport being played, and other management practices (mowing, verti cutting)

How much to apply?
As a general rule, no more than 5mm should be applied at any one time, as any more will smother the grass and create a thatchy fibrous surface, but this is really down to the funds available, there are machines available that can generate top dressing from existing surfaces, and these may be of some use to organisations with limited budgets

7) Top dressing is the placing of materials on to the sports surface this process is done for many reasons,

1. To help smooth the playing surface. Helps to fill in divots, pitch marks and other types of damage.
2. A smooth playing surface will allow the ball to roll faster and straighter.
3. Top dressing after aeration can improve drainage and soil structure.
4. Other types of top dressing can help with moisture retention such as -peat, compost, leaf mould etc.
5. Soil based top dressing can help to supply nutrients to the grass plant.
6. Some top dressing materials can also help change the soil Ph.

As to the question of when-you only want to top dress when the grass plant is actively growing as this helps the surface to recover with little inconvenience to the player.
A heavy application of top dressing can be applied in spring, as this will help to repair any winter damage, also as the grass is actively growing the surface will soon repair.
A lighter dressing should be applied in the autumn as a heavy dressing could smother the grass plant witch could weaken the plant and leave it open to fungal attack. These are some of the reasons as to why, when and how much we top dress.

8) I work on a golf course and we top-dress our greens 3 times a year. Each time top dressing follows the hollow tining of the greens.
We top dress after hollow coring to fill in the holes that are left, this firstly gives the golfers a better service to play on, secondly it will improve drainage of the greens as the water will pass through the cores of top dressing easier. Thirdly the topdressing makes a good base for over seeding the greens, which are done twice a year.
We top dress firstly in mid march Preferably in dry weather so it can be brushed into the greens easily.
The second time we top dress is towards the end of April and thirdly in September.
Each time I top dress I use approximately 1 tonne on each green.
We also top dress tee's once/twice a year this is normally done in April and seed is also added.
This is done to level slight dips in the tee and also to fill divots left by the golfers.

9) Working on a cricket square requires careful management and forward planning to ensure you get as true a playing surface for the prevailing conditions as possible along with a quality appearance. Part of this process involves top dressing the square.

Generally, top dressing of a cricket square is carried out at the end of the playing season after which the square has taken a real hammering from general play, wear and tear, rolling and close mowing. The end of a season depends on the situation and usage of a square - as early as July for a school and as late as the first week in October for some club squares.

The best time to renovate however is late September/early October as the ground is still warm; there is normally some warm sunshine and also plenty of rain about - vital for the binding process of the loam and also seed establishment and therefore the best time for top dressing. During the summer months, the ground has been dry for long periods and perhaps not as much watering has been done as would have liked. The ground and turf therefore needs renovating to restore it to its best.

Top dressing is carried out for several reasons, namely to restore levels on the table - for example, bowling and batting hollows on the ends will need topping up as do stud scars, stump holes and any other surface damage. Renovation is also the ideal time to top up any undulations in the square, which may hold water after copious precipitation or offer low/uneven bounce on a particular pitch when in use. This is done by giving extra dressing to the affected areas, but not too much at any one time, as the surface may be too unstable for use next season. Severe hollows should be dressed out gradually over a few years.

Top dressing also aids seed germination as the seed uses the loose soil particles as a tilth in which to get a foothold to grow which can be particularly difficult on a cricket square. For end of season renovation you should be looking to apply 250 kg of cricket loam per pitch. So for an average square of 12 pitches, the square would require 3 tons of loam. However, if your renovation plan involves hollow coring your square and removing the cores, you will need on average another 100kg per pitch to compensate for the lost cores (depending on core depth).

You can apply top dressing to a cricket square before the season commences but this is not recommended as the loam will not have time to bind properly to the existing soil and therefore could be detrimental to the quality of your wickets during the forthcoming season. It could be though that you may have lost all your seed from the previous autumn due to drought or to prolonged rainfall, or you may have had such a wet autumn that you have not been even able to get on your square to do any renovation! (Believe me it has happened!). If it is a real must, then it would be better to loam the really needy areas on the square with the least amount of loam that you can get away with and try to use the affected pitches as late on in the season as possible in order to give time for the loam to bind properly. This process should be carried out when you are able to get on to the square to work but long enough before the process of spring preparation where the new soil will not be picked up on the roller. Early February would be a good time. Topping the ends up should not pose too many problems and will not affect how the pitches play, but again, you should try and refrain from using these pitches until as late in the season as you can. Ends can be dressed out in spring as late as the start of the season if you don't use the affected pitches until well on into the season.

During the season, it is good practice to top dress individual pitches during use and after retirement of a pitch, but only on the ends. If you are retiring a pitch after play, you should dress the hollows and scars with the same loam, as you would normally use for end of season renovation to enable you to restore the levels on the pitch. This will help you to have a rut free pitch should you come to use it again later on in the season and also give you the possibility to establish some grass if desired. Top dressing these ends is also important as there is always the possibility that a ball may fly up or deviate in a rut whilst play is on another pitch causing frustration or even injury to a cricketer. Be very careful, however, not to get too carried away when dressing ends by hand, too much will ultimately lead to problems with saddled ends over the years which become a problem with regards to drainage on the square and become an unsightly addition! Better to dress out ruts little and often as required without making each application proud of the surrounding soil. You can always add loam but it is difficult to remove it once bound. You can also dress a pitch that is still in play.

If you are using a pitch on consecutive days e.g. a two-day game, then the scars and ruts will need repairing overnight. There are many methods in doing this and each is individual to a Groundsman. My preferred way is basically to make a plasticine paste out of loam and water and to smooth it into the hollows, cover with grass cuttings, tamp down and to leave overnight before rolling in the morning. Again, make sure you don't over do it as you could still cause yourself problems with saddles over time.

Top dressing of a whole pitch during the season should only be done if a pitch has been severely damaged, e.g. masses of divots taken out at both ends due to play on a wet pitch (knocking the top out). Give the pitch a light dressing (no more than 100kg) and water out. This may well help the pitch recover in time to be used again later in the season depending on the time of year. Try and carry out this operation during any significant break in play on the square (e.g. a half term break in a school or a two week break from home fixtures, etc.). Remember, you still have to use the whole square during a game so you don't want cricketers sliding about on a damp sticky pitch! If you are unlikely to use a pitch as damaged as this again during the season then leave it till the end of season renovation to repair.

10) Application of top dressing in spring on golf greens (bowling greens) helps to level playing surface, top dressing may be applied as and when required during playing season depending on weather and growing conditions.

Main top dressing taking place at the end of season on average 2 to 2.5 tonnes per green especially if hollow coring has taken place, this allows greater root development and helps ease compaction as well as aiding drainage.

On football, rugby, hockey etc large top dressing usually takes place at the end of playing season, verti draining or hollow coring with the top dressing being worked into the holes, over seeding usually follows and as with golf greens the benefits are pretty much the same. The holes filled with top-dressing also create an ideal seedbed.

11) We lightly top-dress our golf greens approximately six times per year during the growing season. A heavier dressing is
applied after hollow tining, which may amount to as much as one tonne per 500 sq.m. We will use approx 120 tonnes per year.

It is important that the top dressing is consistent with what has been used in the past and as close as possible matches our existent root zone. The reasons we top dress are, To encourage deeper rooting, to keep a trueness to the surface, to help break down thatch thus improving air circulation, to firm the surface, to assist in the knitting in of new turf, to protect seed, to improve surface drainage, to help speed up the pace of the greens.

The ideal topdressing used in our application should be lime free, washed and with silt and clay only representing only eight per %. And the sand to be round and not angular and fit into the recommended band sizes.0.25 -0.125.