Dear Livtolearn, I also have a new 4x6 unheated greenhouse. I moved my tomatoe and chili seedlings from inside lights to greenhouse over a period of 3 days in late April. I have repotted 2 times and will set plants in the garden with out hardening further the 1st of June. My gh is set up where it gets full sun from 10am to 3pm only. It is in a corner and shielded from the north and east. It also is shielded from the late afternoon sun. Has pretty good southern exposed. I opened the house up at about 11 everyday and closed it up at about 2-3:00PM. The tomatoes did really well, but the peppers not so well. I had to bring seed grown wave type petunias and seed grown pelargoniums back in as it was too cold for them and they where not growing well. Several other flowers did fine; asters, delphinium, annual lobelia, columbine. I have since opened just one vent and am leaving it that way pretty much 24/7. Things are still doing well. It has been breezy here and that has probably helped the heat issue. I would love to hear all of your experiences with the gh. Thanks June

Hi Bev, I'm not sure what bunks are but I'm thinking you are wanting to build something like a raised bed for your tomatoes inside your greenhouse? We've done the same thing using the Trex recycled plastic/composite boards. But those were so expensive it brought a tear to my eye at the cash register! But they work great and will never rot. You could also use redwood and expect to replace it after some time. Another option would be to use bricks or patio blocks. That's what we have at the back edges of the beds. I agree that avoiding treated wood is important. Thankfully there are plenty of other options.

You'll find that greenhouse growers are split between Determinate type and Indeterminite type plants. Personally I only stick with INDT varieties in my structures using the frame and stringlines as a support; I love it. For field grown tomatoes I use Det. varieties and 2' cylindrical cages. As an answer to your question you can grow anything better in a greenhouse, hybrids and heirlooms. But for a good base tomato you should go with a proven "Workhorse" variety. I always grow Trust & Big Beef and for cherry types Favorita is exceptional. I've tried Rebelski last year and was impressed and this year I'm trying a few Caimen plants. I've been less impressed with Massada, Petenza, Geronimo and Caruso but others have liked them. What I would suggest is that you look for a variety with Leaf Mold resistance and if any other foliar diseases appear then you can adjust your varieties another year. I've not had Late Blight problems inside my structures even when field grown plants had issues. For field grown Det. varieties I predominately plant LB resistant varieties.

I am in a similar situation as you described. I start my flats in the basement under lights. I have a 8x10 plastic greenhouse that fits over a metal pipe frame, with a zipper door and two high zipper vents, and also a lower zippered vent across from the door. It's now very old, and has lots of tears and holes in the plastic so it's very leaky. It's amazing how hot it gets in there, even with the door and all the vents wide open. But even on a cold cloudy day in the 40F's it will get up to a comfortable 60+F when all the flaps are shut-- even with all the gaps. Because it's so leaky now, I can't use a heater for overnight, so if temps are predicted below 38F, I'll bring my trays back inside for the night. I try to get the seedlings out there as soon as I can after they germinate. They take sun very well just "out of the shell" -- it's what they would get when germinating naturally in the garden. The longer I wait, the more chance there is of some sun damage from a mini-hardening off, because they can get sunburn even through the plastic. (I've gotten sunburned working in there all day in the late spring too.) It looks like some varieties are more susceptible to this than others. As soon as air temps allow, I start setting the plants outside the greenhouse during warmer days, usually only for a few early morning and late afternoon hours of sun to start with. On a sunny 50F day, it can get to 90F and higher in the greenhouse even with all the vents open. If your greenhouse is more weathertight than my leaky thing, your inside temps may get even higher faster, so you for sure should look into some kind of fan. I look at my greenhouse as a transitional step to true hardening off, which is mostly done by my moving the plants in and out of the greenhouse to find the optimal temps. The growth you get from real sun is so much better for the plants than fluorescent lights. Since I'm at home now, I can check on temps and move plants around as needed. But before I retired, some days I would have to make a quick trip home at lunch time if there was a drastic change in the weather, and I either had to move plants in or out of the greenhouse. Overheating and ventilation are the two biggest problems in small hobby greenhouses. A good fan system might work for you, if moving plants around like I do is not what you care to spend your time doing.