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The best time to overseed an existing lawn is in spring and autumn, with germination taking 7 to 21 days in ideal conditions.
Typical daily temperatures need to be in excess of 13ºC for grass seed germination to be successful.
It’s important to choose the right seed for overseeding. First of all, try to work out what grass types you already have in your lawn. You will also need to consider what you use the lawn for, the aspect of the garden, if the soil drains well, as well as the appearance you are trying to achieve.
For a more wear tolerant lawn choose a seed mix containing perennial ryegrass, such as Medallion® Premium Lawn Seed, which is the same mix used to grow our award winning Medallion® turf. It is a blend of some of the most advanced cultivars for excellent appearance and durability, ideal for use in the majority of gardens and perfect for overseeding an existing Medallion lawn. It contains both fine and medium-bladed leaf, with outstanding year round colour, that will establish rapidly.
For shady, drier areas or ornamental lawns a pure fescue blend may be more appropriate and will introduce shade and drought tolerant grasses, which have a fine bladed leaf and rich green colour. This type of seed mix is also ideal if you are looking to introduce finer grasses to a ryegrass, utility lawn.
You may need to select a different seed mix for different areas of your garden or even different areas of the same lawn. For example, a fescue blend for a front lawn and a ryegrass blend for a back garden and a shady part of your lawn will benefit from a higher proportion of fescues in the mix.
1. Mow the lawn to approx 25mm.
2. Use a spring tine rake to break up and remove the layer of dead matted grass known as thatch. Dependent on the depth of thatch on a lawn this process may require a powered scarifier, which can be hired from most hire shops. This will help the seed make contact with the soil allowing it to germinate.
3. Using a garden fork, spike the lawn to a depth of approx. 150mm at 300mm intervals.
4. If your lawn has not been fed in the last 4 months we recommend feeding the lawn before overseeding. The lawn can usually be overseeded 3 to 4 days after applying a general lawn fertiliser, however, you will usually need to wait about 4 weeks after applying a feed, weed & moss killer. (Check the instructions on the product for this.) A pre-seeding fertiliser is ideal and can be applied up to a few days before overseeding.
5. Sow the seed evenly across the lawn. Medallion® Premium Lawn Seed should be applied at a rate of 23g per m².The seed can be mixed with Lawn Topdressing and applied to the lawn jointly. This will save a bit of time and effort working the topdressing and seed into the surface.
6. The seeded area must be kept moist, therefore, water your lawn after 2 or 3 days if no rain has fallen.
7. Specific bare patches can be reseeded without treating the whole lawn. Apply the same procedure as above, but use sowing rates as for a new lawn (Medallion® Premium Lawn Seed at 35g per m²).
8. To protect specific areas from birds consider covering with netting or garden fleece. This should be removed when new shoots start to come through the soil.
9. Try to keep traffic on a freshly overseeded lawn to a minimum for 7 to 21 days.
10. Raise mowing heights to approximately 50mm for the initial 2 or 3 cuts, then reduce down to 25mm over the next 2 or 3 cuts. Never remove more than a third of the grass blade length at any one time and on new sowings ideally never more than a quarter.
Further lawn care advice can be found in our Information Centre. You can also sign up for lawn tips to receive regular lawn care advice, news and promotional offers by email which will help you get the best from your lawn.
For more techniques to help you maintain a healthy lawn, explore our other lawn aftercare advice.
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