Autumn lawn care: what to do from September to December
The gardening season is drawing to a close, beds and lawn are being prepared for winter. But winterising a lawn means more than raking leaves: what you do between September and December decides how your lawn starts in spring. Here you can read what to do when and why.
In short
- September is the best month for renovation: mow short, aerate, top-dress, overseed.
- Use a potassium-rich feed in autumn, no more nitrogen from mid-October.
- Keep mowing as long as the lawn grows. The lawn should go into winter short and dry, not long.
- Clear leaves consistently. With leaves and twigs, use a rotary mower instead of a reel mower.
- November and December are suitable for deep loosening with solid tines.
- Clean tools, have the reel mower sharpened and store everything dry.
September: renovating
Early autumn is the best window of the year for a thorough lawn renovation. The soil is still warm from summer, moisture returns and the seed germinates largely without weed competition. Repair bare patches, compaction and drought damage now, not in spring.
| Step | What you do |
|---|---|
| 1. Mow short | as short as your mower allows, remove clippings and thatch thoroughly |
| 2. Aerate | remove cores with hollow tines, scarify beforehand if needed |
| 3. Top-dress | work quartz sand into the holes with the levelling rake |
| 4. Overseed | spread the seed, work it in with the drag mat or roll it, keep moist |
All the details and why September suits so well are in Why September is the best month for lawn renovation. After a dry summer there is another reason: many soils become water-repellent and let the autumn rain run off the surface. Aerating breaks through this layer, and the soil goes into winter well moistened.
Feeding: potassium instead of nitrogen
In late summer and early autumn your lawn needs a potassium-rich fertiliser. Potassium accumulates in the plant cells, raises the concentration of the cell sap and so lowers its freezing point. The grasses become more frost-hardy and more resistant to snow mould. Nitrogen-rich fertilisers, on the other hand, do not belong in late autumn: they drive soft tissue that frost punishes, and whatever the grasses no longer take up is washed out over winter. More in Feeding your lawn the eco-friendly way.
Mowing: short and dry into winter
Keep mowing as long as the lawn grows, until temperatures stay below about 10 °C. A common mistake is to leave the lawn especially long for winter. Long blades bend over under wet and snow, lie flat and create exactly the damp, airless climate in which snow mould spreads. Stay at your usual cutting height. If you like, raise it slightly in autumn; what matters is that the lawn does not go into winter long. Make the last cut in dry, frost-free weather.
As soon as there are lots of leaves and small twigs on the lawn, a rotary mower is the better choice. It collects the leaves at the same time, and a reel mower’s cutting unit is spared from twigs. More about mowing on our page Mowing.
Clear leaves consistently
During leaf fall, remove leaves and plant debris from the lawn regularly, not only once everything has come down. Under covered grass there is no light, the patches turn yellow and an ideal climate for snow mould develops: a fungus that feeds on dead plant material and spreads in high humidity and cool temperatures. It leaves grey to brown, matted patches that only really become visible in spring. On larger areas, a drag mat takes over part of the raking and lifts the blades so the surface dries faster.
More about snow mould and other diseases in Lawn diseases.
November and December: deep loosening
Once the lawn has stopped growing, it is time for a measure that is hardly possible in summer: deep loosening with solid tines. They are pushed into the moist soil and tilted slightly before pulling out. This breaking angle breaks up compacted layers at depth without removing soil. Over winter, frost helps break up the loosened layers further. Afterwards, spare the area for a while so the lifted soil can settle. How this works with the Lawnpecker is explained in Lawnpecker attachments.
In frost and on frozen ground, however: stay off. Frozen blades break, and footprints are still visible in spring.
Cleaning and storing tools
If you want to enjoy your garden tools next year, clean them before storing: remove soil from spade, levelling rake and aerator with water and a brush, clean the tines with the tine brush, then oil lightly and store dry. Your reel mower has also earned its service appointment: cleaned, sharpened and stored after the season, it starts in spring without delay. For Falkenstein owners we offer our sharpening and maintenance service.
Common mistakes in autumn
| Mistake | Better |
|---|---|
| Sending the lawn into winter long | mow at your usual height until the end of the season |
| Leaving leaves until the end | clear regularly, also in between |
| Nitrogen in October or November | potassium-rich feed, no nitrogen from mid-October |
| Renovating only in October | in September, while the soil is warm |
| Reel mower on leaves and twigs | use a rotary mower, it collects the leaves |
| Walking on a frozen lawn | wait until the frost has gone |
Frequently asked questions
When is the last cut of the year?
When the lawn stops growing, usually in November, once temperatures stay below about 10 °C. Make the last cut in dry, frost-free weather and remove the clippings.
Can I still overseed in October?
In mild areas and with warm soil, until about mid-October. After that the seed germinates too slowly and the young grasses go into winter too weak. September is the safer choice.
Should I leave leaves on the lawn?
No. On beds and under hedges, leaves are valuable winter protection; on the lawn they take away light and air and encourage snow mould.
Do I need a special autumn fertiliser?
A potassium-rich fertiliser, yes. Whether it is sold as autumn fertiliser or is an organic fertiliser with a high potassium content is secondary. What matters is that it contains little nitrogen.
Tools
- Lawnpecker: aerating in September, deep loosening in November.
- Levelling rake: spreading sand.
- Drag mat: working in sand and seed, gathering leaves.
