Advice on using a mini greenhouse correctly

Elsmandino · May 2022

Afternoon all.

I am very new to gardening (only really got into it within the last 6 months or so) but have really caught the bug, now, and very keen to learn.

I recently bought a 5-tier mini greenhouse and, for the first few days it was brilliant - some seeds that were lying dormant for weeks suddenly sprouted.

However, one of the days was particularly hot and sunny and I had some chilli pepper and bell pepper seedlings that wilted and died.

I would be really grateful for any advice on how to actually use a mini greenhouse - i.e. I realise, now, that you cannot just fill it with everything you have, water everything in the morning and leave the door shut all day.

Any beginner tips would be much appreciated.

Fairygirl · May 2022

HI @Elsmandino - is it one of the plastic ones?
If so, they get very very hot, even on days which aren't that warm, so they need to be really well ventilated, and then closed up early enough later on. The temps swing from one end to the other far more quickly in them than in a conventional glassed greenhouse.

Elsmandino · May 2022

Thanks, Fairygirl.

Apologies - yes, it is the plastic type.

I had no idea that they needed to be opened in the morning and closed at night. Am so glad you told me that.

I wasn't sure if you needed to take some plants out during the day and put them back at night.

As a general rule, are all plants/vegetables/fruits suitable for a greenhouse?

I have all sorts of things in there at the moment and wasn't sure if some should come out after they have started to shoot.

Fairygirl · May 2022

It depends on the plant as to whether it needs any protection. It's a very broad subject

The problem with the plastic ones is that they don't offer much protection from cold weather - fine for keeping rain/snow off young plants. I always had one for growing tomatoes, as they aren't suitable for outdoor growing here - the climate is too inconsistent.
They're also prone to blowing away, so your location is a major factor. I now have a little polycarbonate one, which is better, although it's still fastened to the wall because of the wind. I don't really have room for a decent sized greenhouse.

greatnorthernexotic · May 2022

Keep an eye on minimum and maximum temperatures on the forecast.
When daytime temperatures are high, open the door in to morning. I'm leaving my mini greenhouse open now for the summer, since the lowest nighttime temperature forecast here is 8 celsius.

Fairygirl · May 2022

The important thing is to close it early enough if there are vulnerable seedlings or young plants. Cold can be trapped inside just as easily as warmth.
It comes down to location and the type of plants in it though.

didyw · May 2022

I use mine for potted on seedlings, overwintering tender plants and cuttings. I don't always remember to zip it up again at night but that is not as bad as leaving it zipped up throughout the day - though I have been guilty of that too. Without keeping a close eye on things and keeping them watered and aired it is all too easy for things to wilt and die.

I lost the previous cover - those storms took it clean up and away! The thing itself is weighted down with bricks at the bottom.

Fairygirl · May 2022

I always had to attach mine onto the fence/wall - a bit of washing line round the top, above the zips. Weighing them down is no use here - they just rip when the wind catches them.
The wooden/polycarbonate one has vine eyes around the section at the top of the doors, with line fed through and attached to the wall

Elsmandino · May 2022

Thanks everyone - am so glad that I only got the thing the other day.

Hopefully, I can undo any damages on the plants that have yet to die.

I should say that I am in Essex and the greenhouse is pointing south - as such, there is the risk that things could get very warm in there.

I am definitely going to keep a much closer eye on the forecast now and, as advised, try and remember to shut the door as soon as temperatures start to drop.

Out of interest, do you think it is worth buying a temperature/humidity gauge or do you think they are a bit pointless?

Fairygirl · May 2022

A thermometer is useful - if only to show you the range of temps that can happen. They can get into the 30s quite quickly at this time of year, let alone summer, and I'm guessing your temps will be considerably different to mine

I think it might be worth looking at re siting it, or else getting some shading that you can rig up.
If you watered your little plants, and got them somewhere with a more even temp -[maybe in your house?] they might recover. Would be worth sowing more though.

BeeCee · May 2022

I have a small plastic mini greenhouse mounted atop a cart. This is the second one I have had and when new took the opportunity to rebuild/strengthen the weak points I discovered with the first one. I put vent holes in the sides towards to top to let out excess heat and taped each side of the zippers because that is where the old one ripped from the strain of opening and closing. I keep in an area of shade with a little dappled sunshine in the morning. It doesn't get very hot but also doesn't get too hot. It does keep the rain and wind off of the seedlings waiting for the weather to warm up to be put out.

Advice on using a mini greenhouse correctly

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