Thanks for your answers! So whats the minimum temp it can be Outside for the seedlings to be happy in the greenhouse? Can it be close to freezing as long as the suns shining to heat up the inside? Sorry for the questions but im not that familair with the facts of greenhouses.

Hi dolivo, funny you should ask this. I had the exact same question two months ago when I bought a very similar greenhouse. I also purchased an inexpensive thermometer to hang inside. One caution. Tie it down or the first strong wind will catch the plastic and flip your precious little seedlings to the ground. Spoken from experience - lol. To answer your question, my greenhouse was never more than about 10 degrees warmer. On cold nights I zipped both sides to the ground and checked the thermometer early, midday and just before bed a few hours after the sun had set. We had cquite a few nights in the mid 30s. The greenhouse at that time was around 45. My tomatoes did just fine. Everything inside faired well. I didn't lose one plant. On colder nights, I brought tomatoes and peppers inside but left lettuce, cabbage, celery , etc. outside in the greenhouse. Those things survived nights as low as 28. Now the heat is another story. Boy does it get hot inside when the sides are zipped. I unzip every morning before 8am, to allow for air circulation, but even this doesn't cool it down inside. It still gets hot enough to bake your plants. Tomatoes dry out quickly and need watering daily. It was 72 the other day. The greenhouse thermometer, in part shade, read over 80! Don't place it in direct sun all day unless you have time to nurse it. If you do choose a sunny spot, You will need to check plants often throughout the day. Mine is east facing and gets sun the first few hours of the day. The plants are growing nicely. I should note that my greenhouse is stuffed full of plants. I think that somehow impacts the internal temps. If you have to leave it unchecked for a while, it's better to leave it unzipped. On cold nights, the plastic still provides adequate protection from light frosts.
April

P.s. The heat and humidity are great for seed starting. My okra loves it in there!

Wow! Everyone replied before I could finish my long post. LOL

Wow thanks happyhome for great details! I would assume that once outside temps warmed to say, 65 or above, one wouldd just take the plastic covering off converting the greenhouse to just shelves.
Right now at my house its 50 degrees with a chilly breeze and partly cloudy.
P.s. does anyone know how long its supposed to take cucumbers to sprout? Its been more than 10 days and nada while everything else is up and growing.

My seedlings in the greenhouse

I have the same greenhouse and the doors are open today. It gets very warm and humid in there.
I have had my seedlings out on a 35 degree night-zipped it up just as the sun was setting and the plants were fine overnight.

Dolivo, glad to help.

Cukes should germinate within a few days if soil is warm enough. Are the seeds fresh? I'd add bottom heat for 2-3 days. If that doesn't work. Try new seed.

Here's a pic of my greenhouse a few days after I got it. Looks more like a grocery shelf I know, but I used the containers I had on hand that day.
{{gwi:40812}}

well, the cuke seeds were purchased recently. I think they are Burpee brand, I will try some bottom heat to see if that helps.

You might want to do some reading about these set-ups over on the Greenhouse forum here for more opinions.

Dave

I just got the same greenhouse. I planted the seeds yesterday. Just now the temperature in there was 124°. Since this is day one, do you think the seeds have been sterilized? This morning the temperature was around 54°. The thermometer may have been in direct sunlight, The pots were dry although there was a lot of humidity in the greenhouse. If the seeds germinate, too much humidity in there will be bad too. Do you think the seeds are dead? I saw one reference that said 140° would kill most seeds. I guess it is obvious that I need to move it somewhere where the seeds will not get as much sun. Yikes!

The way you regulate temperature in a greenhouse is with ventilation. Most greenhouses can't be lifted up and put in places where there isn't as much sun. Once the plants are growing, you want sunlight. When the sun is shining on the greenhouse, open up the top and watch the temperature. The less ventilation, the higher the temperature. If you can't open it up wide enough, you're going to need a fan.

P.S. 140F kills all seeds absolutely. Seeds begin to die at 108F. 110-120F for any extended length of time will likely harm them. You can have air temperatures like that when they are in the ground because if the soil is wet, the soil temperature is likely lower. Dry soil? They're probably toast.