June Maintenance

Key maintenance tasks

As you are now likely to be cutting more often, alter the direction and pattern of cut to reduce the amount of stress created by turning circles and the problem of grass 'napping'. Where you can, make large turning circles or even three-point turns.

Heavy divoting will be required on tees, fairways and surrounds as more and more play gets underway. Warm weather and occasional or sporadic rain will help quicker germination and establishment. If you have any bare areas, renovate them to reduce potential levels of weed or poa invasion as the growing season continues.

As the sun comes out and it gets dry, more and more players will be on the course which means the pressure is on to produce a high quality playing surface. Remember it is important to aerate and topdress little and often. When it is warm and dry, don't use tines that will leave large holes (e.g. slit tines) as the ability of the hole to recover will be decreased in these conditions.

Dry weather means irrigation systems will be in use often. Ensure that all pop-ups and central systems are working properly. Clean the system and make sure the sprinkler arcs are correctly positioned. You can trim around the pop-ups and valve boxes to aid presentation and increase the speed of the work during busy times in the morning.

You want to be using the pop-ups when the surfaces need moisture because this is much better than applying water at set intervals when there are few or no signs of stress.

What about your water quality? What pH is it? Is it suitable for your green? Check filters on recycled water systems - poor water quality will affect plant growth and sustainability.

You will now likely be mowing between every day to twice a week and this can vary depending on how the grass is growing and the standards set by the course manager. Height of cut will also vary - this depends on the type of course, course expectations, sward type and mower type. The mower heights listed below can be used as a guide.

  • Greens: 3.5-6mm
  • Tees: 10-15mm
  • Fairways: 15-20mm
  • Rough/semi-rough: Mow and tidy up

Remember to place as little stress on the grass now for best results later in the year and never remove more than a third of total grass height in each cut.

Regularly change hole positions (most course will do this three times a week) but exactly how often you do this will be dependent on several other factors such as green size, green construction, tournaments, amount of play and the condition the green itself is in. When it is wet, you will find the hole may wear more quickly and this results in a crowning effect and surface wear. This wear becomes more apparent if thatch problems are affecting the green. In this case the hole will tend to wear quickly and form a depression caused by the placement of golfers' feet.

it is essential to apply light topdressing of sand/rootzones to maintain surface levels preparation with 'little and often' being a sensible approach. Continue aerating using a combination of micro, needle or star tines for maximum effect and minimal turf disturbance. An alternative is a sarel roller but the goal here is to 'vent' the rootzone and allow water to move quickly from the surface into the rootzone with the result that the turf will root deeper.

Continue fertiliser treatment and turf tonic as per your regular programme. If you are not using a fertiliser programme, get your soil tested and try an independent soil analysis company for an impartial set of results.

Most of you will have applied a strong fertiliser in March and depending on weather and green conditions may have already applied or are considering applying another dressing of fertiliser to keep growth balanced. Reduce the nitrogen and phosphate elements applying something similar to a 9+7+7 NPK fertiliser. Greenkeepers are also using a programme of base feeds which can be topped p with liquid fertiliser. Generally, USGA sand-based greens are more hungry for fertilisers compared to pushed up soil greens. One option is to use straight compound fertilisers. These act instantly to the conditions, rather than slow-release products that can initiate or stimulate growth when you don't want it.

Colour up the greens using an application of iron and seaweed products ahead of competitions and tournaments.

We have recently seen some take the approach of using compost tea formulations and topping this up with tonics and seaweed extracts. Whatever you choose, apply a balanced feeding programme so you maintain the plant's health.

Your choice of materials and how well they work will be dependent on soil type and weather - moisture and air temperatures are the catalyst for growth.


Grass growth levels will reach their peak in June so this means lots of mowing and a greater requirement for essential nutrients. Monitor your playing surfaces closely for any sign of nutrient stress and make fertiliser choices based on soil sample results from the spring.

This increased rate of growth will lead to increased accumulation of thatch. There are many ways to reduce this and it is vital you take steps to do so because it will reduce the chance of disease outbreak in the future as well as other problems.

You should be in the middle of your feeding programmes now but regularly apply SeaAction seaweed and BioMass Sugar to help plant function, stress tolerance and soil biology. If granular feeds are being used, liquids can be used to supplement growth at specific times when it is required, for example for competitions or in between maintenance operations. This gives the turf professional fine control of the plant.

There may have been some red thread about recently but simply feed that out with a small dose of nitrogen. Don't apply a fungicide as red thread is a superficial disease affecting the leaf of the plant and has no effect on the crown; unlike microdochium patch, it doesn't kill the whole plant.

You will need to be on top of your moisture management this month. Some greenkeepers have bought weather stations so they can stay informed about potential evapotranspiration rates within their sward. Don't let the soil dry out too much and keep irrigating as normally as possible. Soaking the playing surface every few days is a better idea than watering religiously at set times. You can buy moisture meters to help you get a better understanding of what is going on underground.

Now you also want to get ahead of dry patch by using a wetting agent. Prevention by application while the soil is wet is much better than trying to cure when the soil is baked or hydrophobic.

Keep an eye on playing quality (PQS) in addition to aesthetic qualities within the sward. Many factors could conspire to reduce either. Monitor your playing and putting surfaces closely and regularly to give you a better understanding of your course. Record findings so you can compare from year to year. Check practical elements like consitency and height of cut with macroscopes and prisms for further insight.

Weeds, pests and diseases

June will see lots of weed growth which you will need to combat using selective herbicides. These are at their most effective when the plant is actively promoting growth and remember to always follow the manufacturer's guidelines.

Undertake work to repair damage made by moles and rabbits as and when it becomes necessary to do so.

Watch out for fungal disease attack and use approved fungicides to treat any areas that become affected. The scarring of the playing surface may be reduced because grass growth is dominant and vigourous during June so there is minimal need for fungicides. However, you might consider using a preventative fungicide treatment prior to important matches, tournaments and events.

As above, red thread may make an appearance, but just use nitrogen to feed it out.

Some areas will see chafer grubs and leather jackets become a problem so think about biological control (like nematodes if this happens to your course. When you apply is crucial. Now isn't quite the right time.

Machinery and materials

Make sure you inspect and clean your machinery after it is used and any damaged machinery is repaired and serviced.

Estimate and order seed, loams, fertiliser, fuel and other consumables on a montly basis.

Dennis Mowers