Lettuce First Water After 43 Days

The lettuce planted in a cup of soil last month has reached 'pricking out' stage (the first true leaf has emerged - see red arrows) and would normally be transplanted into a tray(s). Things have been very slow because of the weather and because I have been deliberately withholding water to show just how well they can manage without it.

As you can see, (and similar to the coriander) despite little action on top, there has been considerable action below ground. The roots reached the bottom of the cup (some 7 or 8 cm (3 inches) about a week ago. To split the plants now would cause quite a bit of damage * to them. But this doesn't matter, since I intend to grow them as a unit, as another community of plants.

Because this is a leafy type of lettuce and doesn't form a head, it should be possible to pot them up into a larger pot and pick at the leaves all summer. That's the theory, anyhow.

I gave them a good drink for now to help them along.

* If you want to prick out your seedlings, best to use shallow compost. This makes separating the plants much easier.

Lettuce Seed Germinating In Soil Cups

5 days after sowing in a cupful of damp garden soil kept at approximately 8 deg C (46 deg F), this lettuce seed shows quite clearly that the root (radicle) is first to emerge from the seed case (testa), complete with delicate root hairs to absorb water from the soil. The white hypocotyl (the part between the root hairs and the seed) has extended. Had the seed been buried, this hypocotyl would also have hooked over to drag the seed case containing the cotyledons (or 'seed leaves') out of the soil as it extended upwards.

GEOTROPISM
Note that even young roots will always grow downwards. They are said to exhibit 'positive geotropism'. Shoots exhibit 'negative geotropism' and grow upwards towards the light.

After 9 days, you can just see the cotyledons (seed leaves) emerging from this seed. Note that they have turned green in the light; the hypocotyl has also turned green. The green pigment cholorophyll is used to produce food (sugar) by 'photosynthesis'. Once this is done, the young plant is independent of the food supply in the seed. This point must be reached as soon as possible.

LIGHT AND TEMPERATURE
Lettuce seeds are sensitive to both light and temperature for germination. We have already seen how lettuce seeds react to light when germinating.

What is also not generally known, however, is that lettuce seed germination virtually 'drops off a cliff' at 25 deg C, with very slow germination even at 26 deg C. But there is also good news: Germination starts at 2 deg C (36 deg F). Peter Thompson shows this very clearly in his excellent book 'Creative Propagation'

Bibliography: Thompson, Peter(2005) 'Creative Propagation 2nd ed' (Pub:USA and UK by 'Timber Press')

Rampaging Lettuce

The lettuce have really come on over the past week. They have done brilliantly, considering weather conditions at planting out (temperatures down to near freezing with an bitter wind). We haven't lost a single one. I did have a photo of what they looked like the next day, but it seems to have got lost.

To give a bit more room and light, the outside leaves can be picked off and used. More will come from the centre.

The slug prevention tape seems to have worked, as well.

P.S. Have just found a recipe for lettuce soup. Looks like I'm going to need it.

Pricking Out Lettuce

Lettuce seedlings getting too cramped. Need transplanting (pricking out). But this cold windy weather has caused a problem.



I like to prick out tiny seedlings at this stage, just as the first true leaf (the one which looks like the plant) is emerging between the two cotyledons. However, with the weather being so bad, I have left it rather too long. So am now forced to transplant them, weather or no weather.




I am putting some in the container outside, which we prepared earlier. No, they are not weeds growing in the centre, they're our spring onions!

Instead of giving them a full spacing of 20cm (8 inches), I am cramming them up a bit (10 cm). If they all take, we can remove some before they are fully grown to make room for the others.

We need to keep a close watch-out for slugs.

With the winter now fast approaching, I am not too hopeful of success.



Old plant trays are really useful at times like these. After washing out and filling with soil (or compost), I am putting some lettuce in as an insurance, in case we lose those outside. I haven't covered the tray (you can buy perspex covers for these trays in garden centres), but have made sure they are well-watered and kept warm but out of the sun. If they wilt too much, I will cover them later (and/or spray with clean water).

You can buy non-heated propagators in garden centres, which are this size (half full seed tray) and ideal for placing on a windowsill. I saw one this year which had a base tray to hold 3 propagators.

The trick with transplanting is to be very gentle with the plants. Take care not to bruise them, and not to disturb the soil around the roots any more than necessary.

Lettuce in Container

Sowed 'Icerberg 2' lettuce seeds thinly in a margarine tub, as per Basil, then covered with 3cm (half an inch) of fine soil.

I am going to grow outside in a container, but because of slugs, and because I want to demonstrate that lettuce can be grown in a pot, I am leaving on window sill at about 15 deg C (59 deg F).

Might be a problem here. Lettuce can fail to germinate at high temperatures. And I am not sure whether or not it requires changing night and day temperatures, as many seeds do.

Instructions say to plant outside, and with this, combined with fact I am still using up old compost (the stuff that failed with the basil), we could have problems. I really am a glutton for punishment.

I am using old compost in container outside. When seedlings are big enough (assuming they germinate!), will plant them out here (around spring onions in centre). Have gone through compost looking for slug eggs and any other predator, but found nothing.

Put some of the new organinc slug pellets (based on ferric phosphate) on floor around base of container to kill slugs harbouring underneath it (the smell attracts them out when it is dark).

Container also has a good wide lip which should be more difficult for slugs to cross.


I am trying out this new copper tape around container. Supposed to be very good. It gives slugs an electrostatic shock if they try to cross it.

Been careful not to put container too close to anything that slugs can use as a bridge.

Only used a few seeds for now. Packet contains about 1250 seeds and it cost 50 pence. So should get a bit of value here.