# Starting seeds in unheated greenhouse



## Mrs. Mucket (Apr 22, 2010)

We built a hybrid greenhouse/shed that has solid north and side walls and has heavy plastic on the south side running from the gambrel roof ridge down to the ground (instead of roof and siding). There are seedling shelves on the south side and electricity for grow lights.

We are in zone 5, last average frost date mid-May. We get average lows of upper 20s in March and lower 30s in April. We get more sun than clouds so there is some solar heat in the greenhouse. 

Does anyone have any tips for the earliest in the spring to start seeds or move seedlings out there with or without heat mats, or how to maximize the solar heat with reflective or black material? We've never had a greenhouse or started seeds anywhere outside our house/garage, so any ideas would be appreciated! Thanks


----------



## happychick (Sep 20, 2010)

I am subscribing to this topic and looking forward to any replies! 
We just put up a hoop house, (I'm also in zone 5), and this will be my first season to try starting seeds in it. Some seeds I plan on starting in our basement under grow lights and then moving them out there.


----------



## Guest (Jan 11, 2012)

I'm interested in any response as I'm also in zone 5 and I have a Greenhouse.


----------



## Callieslamb (Feb 27, 2007)

I started seeds very successfully in an unheated barn for years. I had my plants on shelves and wrapped the shelf in bubble wrap and styrofoam insulation pieces. You could do something similar if you have beds in your greenhouse, by putting up a low tunnel using bubble wrap and wire hoops. If you have tables inside, then just rig up some plastic over them and make sure the undersides are insulate with something. 

I used the scrap pieces insulation with the aluminum covering on the back and sides of the shelf- the bubble wrap on the front. I had my shop lights there and if it got really cold at night, I added a 40 watt light bulb on one shelf (I used the lamp fixture for brooding chicks only with the lower wattage bulb). It was just enough to keep them from freezing. In a greenhouse, you could also cover the plastic tunnels or tables with blankets when it was especially cold. You can also use heat tape under your pots if you have electric available.


----------



## SquashNut (Sep 25, 2005)

I usually start using my green house in mid March. Any seed starting before that is done inside on a table with shop lights over them.
For heat I just set the plants near my wood furnace till they sprout and then the lights are used from then on.
The warm weather crops are still not moved out to the unheated green house untill it is much warmer.


----------



## Mrs. Mucket (Apr 22, 2010)

Callieslamb--the foam insulation is a great idea! I think we even have some. We do have electricity for some 40 W bulbs and will be using heating trays with Christmas lights and sand like these. We also have row cover and some large clear plastic boxes I turn upside down over the seed trays.

Does the ambient temperature matter that much if the soil and seedling trays are warm enough?

Squashnut--we are in PNW too. We've started seeds inside before but don't have space for many this year.


----------



## Callieslamb (Feb 27, 2007)

That is an interesting set up, Mrs Musket. I only used heat tape one time and didn't like it. I'm not sure what happened with it but it didn't seem to keep anything warm. 

I think the plants like a cooler air temp, but if it freezes, it wouldn't be good for them. 

We just built a greenhouse this year so I will be doing some experiments on seed starting myself. If you get a chance you might look into winter sowing. (Sew the seeds in the winter and the will germinate when they are ready). I might have to try some of that too just to see what I can accomplish. I am always too late with my peas. Last year, folks here were saying 'get them planted', but I had 2 feet of snow. So I've got to find a way to get a good harvest from them. 

I have some insulation pieces too and might try using them as an 'A frame' over some of the plantings. I have been using the heavy remay plant protectors this winter on the crops already mature and they have kept my lettuce, carrots, onions and spinach going even until now. I am amazed. We always need to be pushing the envelope since we don't know what will work or not.


----------



## DanielY (Aug 25, 2011)

I start my plants for a mid may planting out. When to start the seed depends on what I am growing. The first seeds I start are early to mid February for some of the early spring colder weather crops. Some seeds I don't start until mid April and they only have 4 weeks grow time indoors. You need to look at each seed and see what is recommended. It usually says start indoors X number of weeks before last frost or says plant out X number of weeks after last frost. Last year last frost came 6 weeks later than average. It got real hard to keep all those plants indoors for an extra 6 weeks and the plants took a beating over it. I now like to plan to plant out 1 to 2 weeks past last frost. it is better to get the plant out the day you planned and planning a week or two later helps insure they will go out on that day.


----------



## praieri winds (Apr 16, 2010)

I have the heat cables and buried them in pea gravel put the flats on top and under lights you can also fil plastic jugs or dark jars with water and place them where they get heat during the day and during the night the heat is released helping to keep the chill out until next day


----------



## Callieslamb (Feb 27, 2007)

I need to get my onions started. Peppers take 12 weeks so I start those the first of Feb. I put everything about a month earlier than suggested. I use black plastic on the ground and low tunnels of plastic on the top. My feed store had wax caps for 20 cents each last year and they were perfect. My peppers loved those. Tomatoes and broccoli, I give 6-8 weeks. I don't think I get an earlier harvest by planting early, but I get more time to play in the dirt.


----------

