When is a seed fully germinated?

I have some impatiens that I sowed last weekend and yesterday I noticed the seed head breaking apart and tiny white stalks bending up from the soil. I don't see the cotyledon leaves yet. When should I remove the dome and take them off of the heat mat? I guess I'd like to know when germination is considered 'complete' so I don't risk damping off.

Germination is complete when the cotyledons have emerged from the seed and have fully opened. I don't use a heat mat myself but as far as I know the seedlings should be left on the heating mat as they grow on.

Actually for most seeds leaving them on the heat mat after they germinate will tend to make them leggy so it's best to take the heat mat away after most of the seeds have sprouted. And I generally take the dome off then too to help prevent fungal problems (sometimes it's helpful to take the dome off gradually so that the change in humidity isn't too stressful...take it off for a little while then put it back on, and gradually increase the time it's off until it's off all the time)

This message was edited Mar 7, 2015 12:27 AM

Blomma,

How often do you air out your dome?

pennefeather:

I do it once a day. I also wipe off some of the moisture that have collected in the dome so droplets won't fall and disturb the seeds that are surface sown.

Thanks - I will try gradually removing the dome as you have suggested. So far the little babies look good but they are still young (no true leaves yet) so my mission is to keep them alive and kicking!

annebrent:
I wonder if those little white stalks you mentioned aren't the first roots growing upwards, or along the soil. I have seen that happen in an enclosed inviroment that is very moist.

By the way, clothespins with the spring works well holding up the dome. I clip it to the frame and lower the top against them.

Here is the seedling flat in my garage window. I have 3 individual flats inside. The dome is open about 1/2" because that window face south. These are perennial seeds that need stratification, the reason they are in the unheated garage. I ususally sow all my seeds in a coldframe but ran out of room for these 3 varieties. I don't expect germination until weather warms and condition is right for the individual variety.

A heating mat should only be used to germinate those seeds that require that temperature. Growing plants too warm, produces a weak-stemmed plant that is harder to acclimate. If possible, grow plants cooler for sturdy growth. About 60-65F at night is about right. Higher during the day is fine.

Great tip with the clothespins!!

I'm a big believer in growing in cool conditions after germination. It does make very sturdy seedlings.

i have a question

if temperature is 50c but other conditions for germination are suitable whether the seeds would germinate or not

please answer me

darklord,
I am not sure what your question is. I will try to answer as I understand what you want to know.

50c (120 F), much too hot for plants, unless they are cacti. If you can sprout seeds and grow plants at 20 Celsius (70 F) is ideal. It also depends on what seeds you are trying to sprout.

Below is seed data base on sowing all kinds of seed. They are listed alphabetically.

http://tomclothier.hort.net/

http://theseedsite.co.uk/index.html

http://www.jlhudsonseeds.net/index.htm

I need to do some research on some new-to-me types of seeds, so I think I will bump this thread up.