To cling film or not to cling film?

Hello everyone,

I wonder if anybody could give me some advice. I am not entirely new to very basic gardening but I am a whole new world when it comes to seedlings and propagating!

I have just planted some pansy and petunia seeds in the hope of creating some hanging baskets a little bit later on. I bought myself a little pop-up greenhouse from a local shop in order to do this because I have limited space in the house.

I have followed all of the instructions on the back of the seed packets and looked at videos on youtube.

I have popped my trays with planted seeds into the greenhouse, should i also cover them in clingfilm? If i was to do this indoors, I would use clingfilm as I don't have propagators with lids. I don't want to bake my seeds!

I hope this makes sense.

Tony

 

Hi @TJJ5621 ,I usually use food/freezer bags. If they're in pots I pot the whole pot in the bag and tie it, if they're in trays I cut them open and tuck them under the bottom.
If cling film is all you've got then use it. It helps to conserve a steady level of moisture and stops them drying out.

 

I would have used freezer bags but we dont have anything big enough for the trays. But using cling film on them within the greenhouse won't cause them any issues?

 

I'm sceptical that it will make a good seal (where as a plastic bag would make a nice little "tent like" greenhouse over the pot).

I use cling film over Tupperware containers, for seed chitting on damp kitchen paper, where I have lost the Tupperware lid. Its never as good / well-fitting as a proper lid, because I can't get the Cling to "stick" to the plastic of the Tupperware, and I'm thinking your Pots would have the same problem.

But maybe you wither won't have that problem, or can work around it?

 

The plastic bags is a good shout, I hadn't thought of it. Although to be fair, the cling film appears to seal quite nicely.

My major concern is that because i have them in a green house, do they require covering with plastic bag/lids/cling film at all considering that is what a greenhouse is good at? I don't want them to die through overheating etc.

 

You could use e.g. cardboard. The aim is to keep the soil-zone moist, so it doesn't dry out at just the critical time when the seeds are germinating. But if you don't get the cover off in time the seedlings will get leggy stretching for the non-existent light (they will think they are buried a bit deep and that they are growing thought the soil and up into the light ...)

Polybag solves that by keeping moisture in, and letting the light in, but yes it will also act as a mini greenhouse. When I were a lad we used to put a sheet of glass on (wooden) seed trays way-back-when ...

The clear plastic propagator lids I have, for seed trays, have "vents" on the top, but i keep those closed, to maximise humidity, until they germinate and then open them to allow some ventilation which counteracts overheating, but still keeps the atmosphere snugly humid.

I think those are the variables that need balancing. If you are in lockdown at home then perhaps? you can check them a few times a day, whereas for folk who would normally be out at work there would be significant risk of overheating / drying out during the day and that would go unchecked, until possibly "too late"

 

If you cover the seed trays keep them in the shade, they will overheat in full sun if covered with cling film or put in a plastic bag.
Personally I'd not cover the pansy seed, it needs a lower temperature than petunia to germinate, too high and the pansy seed might go dormant.

 

As this pop up is outside the temperature range of day and night may give very erratic germination of the Petunias, Pansies not so much. I used to sow Petunias at 20/ some form of 22c and Pansies at 16/17c in a heated prop or even an airing cupboard but always covered with some form of plastic covering but turned over each day.