What is the most important lawn feed of the year?
As winter approaches, many home gardeners in Mediterranean and similar climates tend to assume that the chores and tasks associated with lawn care are over for the year, and that they can forget about lawn treatment until the following spring. It is easy to see why, as most of the grass varieties used in such areas are dormant during the winter, while feeding and dethatching in the autumn seem to make little difference to the lawn's appearance at this time.
However, feeding, if carried out properly, and dethatching where appropriate, help the lawn to recover quicker and grow better at the start of the following year's growing season. What then is correct feeding; when is dethatching necessary, and how should it be done?
Lawn Food
Lawn fertilizer applied at the end of the summer or the beginning of autumn, can contain a relatively high percentage of nitrogen, in order to take advantage of the remaining 6 weeks or so of growing season, before the onset of winter. The closer to winter however, the presence of available nitrogen becomes increasingly irrelevant. In both cases though, it is best to apply a lawn fertilizer containing a high percentage of potassium, as this encourages satisfactory root development, whose benefits as mentioned, will be visible in the spring and help in creating a lawn that is hardier to pests, disease and drought.
The easiest method of feeding is to use a slow release fertilizer. In the fall, the percentages of nitrogen, phosphorus, and potassium, expressed from left to right on the package as N-P-K, should be low in nitrogen and phosphorous, (N and P respectively) but high in Potassium (K). Alternatively, one can use an organic fertilizer, although bulky organic matter, such as compost, while essential for the rest of the garden, is less desirable for lawn care, as it is difficult to spread evenly, and is liable to exacerbate the thatch problem.
Dethatching Lawns
Removing the thatch that has built up through the summer is one of the most important tasks in lawn care and treatment, particularly with many of the species used in hot, dry, summer climates such as Bermuda, Zoie, and Kikuyu varieties. While many home gardeners are aware that dethatching is essential in the spring, less know that it is desirable in the autumn too, as it significantly improves the rate at which rainwater percolates through the soil. It needs to be carried out far less aggressively than in the spring, and only on those species that recover from the treatment. Great care must be exercised with grasses like Buffalo, or St. Augustine, which can be irreparably damaged by over-zealous dethatching.
Over Seeding Lawns
An excellent way of greening up a perennial lawn that becomes dormant in the winter is to over seed with a variety that grows well in the winter, only to fade away through the summer. For this purpose, dethatching the lawn prior to spreading the seeds, greatly aids in increasing the germination rate, which helps the lawn look a lot fuller and greener through the winter.