Another very popular subject on this site is over-seeding of greens in Autumn.
Over-seeding is commonly carried out as part of the autumn bowling green maintenance and renovation program and is very often a disappointment.
You would expect this work to quickly fill in the bare patches and spaces in the sward left by disease, localised dry patch and a host of other green problems, but this is very often not the case…why?
The answer to most disappointing results from over-seeding is “competition”. Competition from the mature, indigenous grasses whether fine or weed grasses like annual meadow grass usually reduces the success or survival rate from over-seeding to a very small percentage.
This quite often comes as a surprise to greenkeepers who have observed a very good “take” shortly after seeding (7-14 days). At this early stage it is not uncommon to see vigorous lines of dense new seedlings bursting forth from the green. This however, is usually a false reading.
At this very early stage the seedlings are still living off the food reserves in the seed itself, but they very quickly have to turn to what they can find in the soil to survive and thrive. This is when the major problem kicks in, as they are not only competing with each other for light, air and nutrition but also with a mature sward of indigenous grasses and other plants. Then there are the other problems of disease; damping off, a fungal disease that attacks seedling turf is a common problem where seed is sown densely and the onset of winter.
These factors combined can quickly turn what looked like a 99% germination rate into a 2 or 3% survival rate in the long term. So what can be done to maximise the success we achieve with over-seeding:
- Get the seed in as early as possible in the autumn to give it access to sufficient light, warmth and nutrition.
- If you have thatch issue (in excess of 5mm thick) don’t bother; instead concentrate on repairing bare areas with plugs of turf from the corners or if you have to use seed on bare spots, renovate these thoroughly by hand and produce a good seedbed for the new seed.
- Put the indigenous sward under a bit of stress prior to over-seeding by scarifying it severely to weaken it just enough to buy the new seedlings some time.
- Always over-seed with a proper over seeding machine which gets the seed into the soil and applies it accurately into the bargain.
- Make sure there is sufficient moisture to get the plants going quickly.
- New seedlings need a bit of Phosphorous to get their roots going quickly so make sure this is applied but not too heavily.
- Don’t be over ambitious; large bare areas are unlikely to recover fully by simply over-seeding them.
- Make sure you have selected a quality seed mix and that it has a certificate and germination and purity statistics attached.
Over-seeding isn’t the fix all that many people expect it to be, but go into it with your eyes open and it can be a very useful tool in the greenkeeper’s armoury.