Getting Wild Seed to Grow
Why is it so difficult?
Is this just a myth or is it true. Yes, it is true! Wild flower seeds can be very small, but so are many of the grass seeds which are used. There are two key factors to trap the unwary:
Wild flower seeds grow very slowly. Most are perennials and they are easily outgrown by annuals, which only have a single season to grow, flower, set seed and create another generation. Coarse grasses also offer ferocious competition since they grow well in the UK’s mild climate.
Not all seeds germinate in the first year. Wild flower seed growers take great care to maintain the “wild” characteristics of native wild seed and avoid continuous cropping without adding in new seed from the wild. Uneven or erratic germination may be inconvenient for growers of wild flowers but it happens to be a key survival feature. If all the seed that was shed in one year met with a disaster, the future of the species could be jeopardised.
Essential steps in growing wild flower seed.
1. Make a first class seedbed.
Create as good a seedbed as possible as if you were sowing a new lawn.
Remove all weeds.
Break down all clods or large lumps – no golf balls if possible!
Consolidate well. If footsteps can still be seen, roll lightly.
2. What about the weeds?
These fall into two groups:
a). Weeds you can see.
Spray off weeds you can see with a herbicide. Glyphogen is best for grass. If the vegetation is unmanaged and rank, it may be best to cut and clear and await re-growth before spraying. When all looks dead, rotovate and rake off /harrow dead grass etc.
Difficult weeds include creeping thistle, which usually can only be sprayed in May with a special product when it is 6- 10 inches tall and growing actively. Nettles and docks are also best sprayed in May with Grazon 90 or similar.
Organic growers may prefer to avoid herbicides, but you will need a lot more time and have the weather on your side.
DO NOT SOW THE NEW SEED YET!
b). Weeds you cannot see = dormant seed.
This is all about dormant seed, which causes major problems for the unwary. It is possible to do all the work under “weeds you can see”, sow the new seed and end up with all the weeds you started with. Many commercial grasses, especially ryegrass leave masses of dormant seed lying about. If you create a beautiful seedbed, these will all sieze the opportunity, germinate and grow like mad. There are many other weed species which can survive for years in the soil such as docks, cocksfoot, Yorkshire fog grass and ryegrass and which can cause serious complications.
3. Dormant weed seed – annuals or perennials.
Annuals include species such as speedwells, fat hen, groundsel and poppies. If these are cut or mown off during the first season, they will not recur, because being arable weeds, they depend on cultivation to germinate. Ex arable land and cultivated land will have large amounts of these annuals and many fewer perennials. Years of herbicides will have eliminated most perennials on arable land. In addition, perennials have less good seed dormancy and this is sadly the case with most of our wild flowers.
It is useful to assess the risk of dormant seed when considering establishing wild flowers:
Low risk situations: old kitchen gardens/cultivated land/ex-arable land.
High risk situations: old paddocks, permanent pasture, unmanaged land.
4. Reducing dormant seed.
Dormant seed is going to cause trouble if it occurs in the top inch or so of the seedbed. If it can be encouraged to germinate before you sow your new seed, much unwanted competition will be removed. Weeds generally grow much faster than wild flowers so they pose a serious threat.
Timing. The secret of success is to work with the seasons. If an area of high risk ground is cultivated in early spring with the aim of sowing in April or May, the ground will be too cold for any weed seeds to germinate and you will have no idea as to how much weed competition is going to occur. However if the ground is cultivated in July or August with the aim of sowing in September, the ground will be warm and any weed seeds will germinate rapidly leaving you plenty of time to either spray them with a herbicide or harrow them on a dry day. If you harrow them, this will bring up more dormant seed and the next time round you may have to spray if it is getting close to sowing time. Once you have given this final spray, do not harrow or do anything else which will disturb the soil surface because this will only bring up more dormant seed. A good roll will finish off the job.
The best method is to plan well ahead so that you have most of the growing season to harass the dormant seed. Thus:
May – spray (knapsack) or tractor mounted sprayer for larger areas.
June – after two weeks, plough or rotovate before the onset of a “barbecue” summer which could turn the ground to concrete. Rake off dead material.
July- September – Create a seedbed. Every time the green haze of weed seedlings appears, harrow or rake on a dry day. This will get rid of one germination and bring up another one. Repeat the process. This can be done two or three times. If the green haze persists into September, use a herbicide as above and then broadcast the new seed. The job is completed with a final roll to get the seed into good contact with the soil.
If an area is infested with docks, spray off, sow grass seed only and remove docks which persist with a selective herbicide. When stability has been achieved after two years, introduce wild flowers gradually with 9cm pots. Take great care when disturbing the soil surface.
In the early days of establishing wild flowers, topsoil removal was recommended in order to reduce fertility. The good news is that you don’t have to remove it because the parasitic plant yellow rattle will reduce the grass growth which was a problem in fertile soils – see managing your wild flowers. In any case, topsoil removal can only be done on small areas and since topsoil is so precious, it does not seem a good idea if there are alternatives. However, topsoil removal from small areas of chalk can be very helpful in establishing difficult plants such as horseshoe vetch which may be crucial to the survival of certain butterflies.
6.Best time to sow?
As described above, autumn is best for reducing dormant seed. There are other reasons for choosing autumn.
Wild flowers shed their seed in the autumn, so autumn sowing is closest to what happens naturally.
Wild flower seed appears to germinate best if it is left on the soil surface. This works well in the autumn when you have warm ground and falling temperatures. In spring, because temperatures are rising, seed has to be covered which tends to lead to patchy establishment.
7.Sowing small areas.
This is easier said than done. Wild flower/grass seed mixes are sown at very low seed rates (almost a tenth of grass seed rates). Consequently, it is very easy to run out of seed, which is embarrassing! Wild flower seed is expensive and the accompanying grass seed has to be sown at low rates to prevent it competing too much with the wild flowers. If you are sowing an area the size of a tennis court (approx 1000m2), you will have 4 kgs of seed.
You will need:
A bag of canes, usually 3ft.
A heap of sand or sawdust.
Divide the seed into 4 x 1kg heaps, one in each bucket.
Add enough sand or sawdust so that each bucket is full and mix well with the seed.
Divide the area to be sown by four and mark out the first area by laying canes on the ground.
Test your sowing rate by scattering the bulked up seed from bucket no 1 in the first area. Aim to have some seed over, in which case you can go over it again. If your sowing rate is too heavy and you run out, all is not lost because you still have three quarters of the area remaining and you can adjust the seed rate.
There are endless permutations as to how you should scatter the seed, but I use a 2m strip.