Tomato seedlings

Yorky

I sowed some tomato seeds in modules with a plastic lid last Sunday (8 days ago) & placed them on a heat mat in a lean-to greenhouse.

The seedlings are now touching the top of the lid - can anyone advise what to do next?

I'm thinking of potting them up & then:

placing clear plastic bags over them or
putting them on the kitchen window board (but the house is not warm)

Also, I sowed celeriac & onion seed at the same time but they haven't germinated yet - is that normal?

Thanks in advance.

redser7

You want to be careful about keeping them in the progagator with the lid on. It can be very humid and cause damping off desease which will see them fall over dead. And even though it is cold out there, when the sun comes out the lean-to and propagator can heat up very quickly and kill them too.
Best place for them is indoors on a sunny window ledge. Take them away from the window ledge at night as they can get frosted there. Tomato plants can take 10 degrees so you should be able to maintain that no problem. Even make a bit of space in a press and pop them in there at night, then back out onto window ledge in the morning.
When you pot them up choose a 3 - 5 inch pot and pot the seedlings deep, with the seed leaves resting just above the surface of the compost. Weather permitting you can put them in the lean-to during the day in early april to start hardening them off. BUtr always watch the heat and ventilate as necessary.

Markcheese

A friend of mine starts her toms (and she does loads) in a hot box( wooden box with a layer of sand over a heating element) at night she covers the box with either plastic or bubble wrap.... Seems to work for her...
Onions are slow to sprout, not sure about celeriac....

Yorky

Thanks for the replies.

I kept the lid on to keep the moisture in as a constant 20 degrees will dry out the soil otherwise, then to bring them out of the lean-to to water will dramatically lower the temperature.

There are just two cotyledon leaves with leggy narrow stems at present - is it too early to pot them up?

redser7

Once they germinate they can withstand lower temperatures. Room temperature is fine so long as they get good light on the window ledge. Keeping them too hot can result in them getting leggy. So don't worry about 20 degrees, that's more for germination or growing on something like peppers. You can prick them out with just the seed leaves. But best to wait until you can at least just see the true leaves starting to come. That is a sign that the roots are developing nicely and the plant is ready to support itself. It shouldn't take too long. Potting the stems deep up to the seed leaves will take care of the legginess and new roots will grow out from the buried stem.