LETTUCE SOWING ADVICE, PLEASE
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PitshangerDigger
- KG Regular
- Posts: 1
- Joined: Thu Mar 30, 2006 1:55 pm
- Location: Ealing, London
Can someone please give me some advice on sowing lettuce at this time of the year. I have sown Lakeland in a seed tray in an unheated greenhouse but am a little worried that they may not germinate due to the daytime temperature getting above 50 degrees on a sunny day. What's the best way to sow lettuce now - in a cold greenhouse and then transplant the seedlings or in the open and thin out?
THE PITSHANGER DIGGER
i sow a pinch of seed, usually a mix of varieties, in a 3 inch pot, leave to germinate in the polytunnel. pot the seedlings on into individual pots when an inch or so high. then plant either into the tunnel beds or outside when they have outgrown the pots. i usually sow a new batch every month or so. in mid summer the freshly sown pot will be started on a north facing windowsil to avoid the heat. once they are growing the heat doesnt seem to hurt provided they are well watered
Hi PHD,
You are quite right to seek advice with loss of germination with Lettuces. If the temperature is 50C or over then they probably will lock up and not germinate and then around October they will break dormancy and grerminate when you no longer need them.
For those who may scoff 50C is very easily attained as early as February in an inadequately ventilate Greenhouse or Tunnel. I got caught out by this in 1998 and had next to no germination from many thousands of sown Lettuce seed and had to resow the whole lot. In 1998 I was producing over 40 varieties of Lettuce and a 60ft x 30ft tunnel lined out with 6 benches x 60ft with 3740 modules every 12ft run of bench. (112200 in all)So do make sure that where you are producing seeds is adequately ventilated so that temperatures do not rise unduly in the greenhouse or tunnel.
You are quite right to seek advice with loss of germination with Lettuces. If the temperature is 50C or over then they probably will lock up and not germinate and then around October they will break dormancy and grerminate when you no longer need them.
For those who may scoff 50C is very easily attained as early as February in an inadequately ventilate Greenhouse or Tunnel. I got caught out by this in 1998 and had next to no germination from many thousands of sown Lettuce seed and had to resow the whole lot. In 1998 I was producing over 40 varieties of Lettuce and a 60ft x 30ft tunnel lined out with 6 benches x 60ft with 3740 modules every 12ft run of bench. (112200 in all)So do make sure that where you are producing seeds is adequately ventilated so that temperatures do not rise unduly in the greenhouse or tunnel.
JB.
Gosh, John, that's going some on numbers!
It makes 60 at a time look piffling. I never like to put all my eggs in one basket.
I am leaning heavily on 2 varieties at present, Counter which is a medium cos from D T Brown, 3 seeds to a pot, no more, single when you can handle them, and Pandero which has some popular red tinge and is always pill seeds (pelleted) and has a near-100 percent germination so single sowing and no thinninh required.
I believe 10C/50F is a bit low but there certainly is a threshold. Many growers are sowing in late afternoon so that the most critical period is in the coolest part of the day.
By raising in modules one can minimise root disturbance and thus not have the chore of thinning out incurred in in situ sowing, but even so by May one looks for a cooler shady spot for lettuce and radish and a place to start off the next generation of watercress.
Allan
It makes 60 at a time look piffling. I never like to put all my eggs in one basket.
I am leaning heavily on 2 varieties at present, Counter which is a medium cos from D T Brown, 3 seeds to a pot, no more, single when you can handle them, and Pandero which has some popular red tinge and is always pill seeds (pelleted) and has a near-100 percent germination so single sowing and no thinninh required.
I believe 10C/50F is a bit low but there certainly is a threshold. Many growers are sowing in late afternoon so that the most critical period is in the coolest part of the day.
By raising in modules one can minimise root disturbance and thus not have the chore of thinning out incurred in in situ sowing, but even so by May one looks for a cooler shady spot for lettuce and radish and a place to start off the next generation of watercress.
Allan
I checked on this website
http://tomclothier.hort.net/page11.html
One sees that for lettuce the optimom percentage is obtained at 32F/10C, then it tails off gradually until at 77F/26C it drops suddenly to near zero. Of course at 0deg C.one would have to wait too long for germination so a bit below such as 10-20C and no short peaks in temperature is desirable.
Allan
http://tomclothier.hort.net/page11.html
One sees that for lettuce the optimom percentage is obtained at 32F/10C, then it tails off gradually until at 77F/26C it drops suddenly to near zero. Of course at 0deg C.one would have to wait too long for germination so a bit below such as 10-20C and no short peaks in temperature is desirable.
Allan
I set up a bench on the North-east facing wall of my house and germinated lettuce here during the hot summer. Also good for others like parsley that dislike hot temperatures.
I don't suffer from insanity .... I enjoy it!
Vivianne
Vivianne
The critical period apparently is in the very early stages of germination - just after the first watering. I always sow in the evening and leave the trays out overnight. In the morning they then get moved to somewhere with some protection. They certainly don't need any extra heat from now on unless very cold weather is expected.
John
John