Autumn Weather

We are starting to see significant changes in both soil and air temperatures, dropping down into single figures. This coupled with clear, cloudless nights brings about the appearance of some early morning dews and frosts.

Dew forms when a surface cools to a temperature which is colder than the air next to the surface. Dew is water that has condensed from some of the water vapour contained in the air. If the layer of air next to the ground were actually cooling, then fog would form. Instead, it is just the surface (for instance, grass) that is cooling, and a very thin layer of air next to the grass deposits some of its water vapour on the grass.

Fungal disease

The combination of early morning dews, warm and wet weather and diminishing daylight hours increases the risk of fungal disease outbreaks. The right conditions to trigger these disease attacks are weakened or susceptible plants, a disease-producing organism (pathogen usually fungi) and weather conditions which favour the formation of fruiting bodies and spores (moist, mild wet conditions).

Most diseases that are occurring now have responded to the unusually warm, autumn weather conditions. Boundary layers around the leaves have stayed very moist and humid. Relative humidity is important for spore germination and penetration of leaf tissues, and constant wet conditions will allow the development and transportation of active fungi spores.

The pathogens that cause these diseases are always lying dormant, waiting for the ideal conditions to become active. Once these spores are activated, and have found an appropriate host, they are able to grow and reproduce themselves, spreading new spores and infections to other areas of turf. This cycle continues whilst favourable conditions prevail.

Understanding and implementing works that can break up the disease cycle will help reduce the opportunities for disease development and outbreak.

However, the best mode of action is a preventative one, which will see you carry out the relevant cultural practices to break the cycle of the disease. Brushing to reduce dew deposits, good aeration and feeding programmes will help prevent and hopefully, reduce the incidence of diseases in your turf.

Leaves

This autumn period (October – November) will also see us having to cope with the job of raking up and removing leaf debris from lawns. Luckily, this back-breaking work has been made easier with the development of a range of hand held, tractor and dedicated leaf sweepers, blowers and vacuums.

In fact, I am currently testing two STIHL backpower blowers, the BR450 C-EF model and their battery powered BGA200.

I already have my own BG56-C model which I use daily and is probably my most used piece of equipment to keep surfaces clean and tidy.

Tree work

For me, one of the most important jobs is to carry out any relevant tree works. This may be a programme of tree felling, tree pruning (crown lifting, reducing) or tree planting. However, the most challenging of these tasks is the choice selection and planting of new tree material.

Planting trees and hedges should not be looked at in terms of being a chore, or that it may be too expensive. Planting trees and hedges is about leaving a lasting legacy for future generations to enjoy and benefit from.

Many factors must be taken into consideration when planting trees and hedges. First and prior to any planting, think carefully about what you are trying to achieve.

The choice of planting material will need to be carefully considered. Should it be a single species, deciduous or evergreen, or a mixture? Should they be flowering or non-flowering, thorny or smooth barked?

It is also important to choose the right plant for the right place; the topography and environmental factors of the site will dictate what can be planted and where.

The condition and age of the plant material is vitally important in terms of dictating both the successful establishment and how quickly you want the hedge or tree to achieve its objective.

However today, with so much more user-friendly accessories available to aid planting when excavating, staking, feeding and watering, the job of hedge and tree planting has been made much easier and more flexible.

Also the array of machinery now on offer to aid planting and cultivation is immense; rotavators, trenchers and small diggers are relatively cheap and, in most cases, may be hired. We have also seen the introduction of tree spades that are able to remove and replant large trees.

Always source material from reliable nurseries and ensure it is true to cultivar/species and in good health. In recent years, a lot of imported nursery stock has been blighted with disease; the recent ash die back disease being a prime example. This has affected the supply of many trees in the UK in recent months, with nurseries having to dispose and burn their stocks to prevent its spread.

Article written by turf expert Laurence Gale.