Building my greenhouse, some questions ..

[jam583]

Hi! New guy here .. I am building a greenhouse over the next week or so. Tomorrow I am pouring the concrete slab and will anchor it into concrete.

This is all new to me and I have a few questions I hope some can help with:

1. I plan to build a box that is the length of the greenhouse, about 2 feet wide, and fill with soil. I'll put holes in for drainage, etc., but wanted this permanent soil area. My goal was to plant Tomato plants directly in it and other vegetables I usually put in the ground. I figured I would make it 8 inches high with soil in it. Is this realistic? I realize I may only get 7 tomato plants in it with proper spacing.

2. What is the lowest temperature that I can do this in? At night, it will fall to about 30' right now. I will have two 60 gallon barrels (painted black) of water to the right (will put wood on top to double up as a shelf. During the day, I suspect temp will be ok for winter.

3. What vegetables grow best in pots? How much soil and how big of a pot?

Looking forward to any and all feedback on my journey.

[Bobberman]

Are these double pain panels!? Will you have electric in it? Looks nice especially the 6 by 14! Put the water barrels on the north wall so the light is not blocked on the sun side. Put insulation behind the barrels! but not touching them so the air flows around the barrels! Put the barrels on a insulated surface like a one inch layer of Styrofoam! I think you are better putting each tomato in a 5 gallon bucket so it can be mover outside since the tomatoes will be to close and the heat will be intense in the summer! I like a fan blowing on the water barrel when the inside temp is above 50 during the day! This gives your water a jump of a few degrees for the night low temp! Hope this helps! The more water storage the better a 100 gallons for the small greenhouse should work . The 14 foot greenhouse I would use 200 or more gallons in 50 gallon drums plastic or metal!

[rainbowgardener]

Congratulations on the new greenhouse!

It is certainly exciting, but it sounds like you might have wanted to do more research before laying out that much bucks. Your greenhouse is single paned, which means it will pretty quickly equalize to the ambient temp at night. The water barrels will slow that down some, but I doubt could keep it above freezing all night if the temps are very much below freezing. You are in zone 7A with a milder winter than me, so maybe. Tomatoes won't set fruit if temps are going below about 55 deg., but from seed you have a couple months of growing them out before they will be to fruit set stage, so it will be warmer by then. You still might need to start your seeds indoors on heat mats, because tomatoes need soil temps above 70 for germination. After they are well started you could bring them out to your greenhouse if night time temps in it are reliably staying above 40 deg. You do need a min-max thermometer that records what the temp got down to.

8" of soil is very minimum to grow tomatoes in, over concrete. I think you would be much better off to make it 12". And do be sure about the drainage. And then think 5- 6 plants, not 7, with some smaller stuff around the edges.

Your greenhouse has only one roof vent, which doesn't make for any flow through ventilation. You will need to get one of those automatic thermostat controlled openers. Even on very cold days, if it is bright and sunny, your greenhouse can heat up intensely during the day and cook your plants. Were you planning to leave them in the greenhouse through the summer? Then you will need the door open and fans circulating the air and may need shade cloth or something over some of the windows to keep it from heating up too much.

You can grow almost anything in containers if you set your mind to it and have big enough containers. If you are using smaller containers, like about 2 gallon size, then you will need plants that stay smaller. Peppers are ideal for this and a variety of herbs like basil, sage, rosemary, oregano, parsley, etc. Greens, like lettuce, cabbage, spinach, chard are good for containers.

Best wishes and keep asking questions as you go along! Welcome to the forum!

[jam583]

Are these double pain panels!? Will you have electric in it? Looks nice especially the 6 by 14! Put the water barrels on the north wall so the light is not blocked on the sun side. Put insulation behind the barrels! but not touching them so the air flows around the barrels! Put the barrels on a insulated surface like a one inch layer of Styrofoam! I think you are better putting each tomato in a 5 gallon bucket so it can be mover outside since the tomatoes will be to close and the heat will be intense in the summer! I like a fan blowing on the water barrel when the inside temp is above 50 during the day! This gives your water a jump of a few degrees for the night low temp! Hope this helps! The more water storage the better a 100 gallons for the small greenhouse should work . The 14 foot greenhouse I would use 200 or more gallons in 50 gallon drums plastic or metal!

No, the are single panel. I know it's not ideal, but for my first greenhouse it's what fit the bill. I will have electric in it, burying a line once spring comes. For now, an extension from an outdoor outlet.

Good thought on the stryofoam base for the buckets. Given each is 500lbs once full, I will build a platform and put insulation under it, so no cold air from under rises up.

After much thought, I have concluded buckets are the way to go, especially since I can move them in the summer outside, etc. Five gallon buckets are easy enough to come by.

I plan to put 120 gallons (60 gallon barrels) in the greenhouse + a small electric heater which can heat 120 sq feet (I figure it will actually do 60 sq feet). I will have a ceiling mounted fan for circulation.

This is my first venture into it ... I don't suspect much use in the summer, to be quite honest, but will experiment

[jam583]

Thanks! I plan to have 120 gallons of water (2 60 gallon barrels) and a smaller electric heater that is capable of heating 120 sq. feet. I will be testing it within a few weeks and measure the hi/low temps during the winter. I agree, single pane isn't ideal, but based on my research and budget, it seemed to be the best choice for my immediate needs.

For the tomatoes, I found some good places online that sale bare root that I can plant. I do this with grafted grapevines with great success. Thought maybe I'll start from bare root, versus straight seed.

I have decided to use buckets, no planter box. This will give me more flexability, etc. So, a 5 gallon bucket per tomato plant, etc.

Congratulations on the new greenhouse!

It is certainly exciting, but it sounds like you might have wanted to do more research before laying out that much bucks. Your greenhouse is single paned, which means it will pretty quickly equalize to the ambient temp at night. The water barrels will slow that down some, but I doubt could keep it above freezing all night if the temps are very much below freezing. You are in zone 7A with a milder winter than me, so maybe. Tomatoes won't set fruit if temps are going below about 55 deg., but from seed you have a couple months of growing them out before they will be to fruit set stage, so it will be warmer by then. You still might need to start your seeds indoors on heat mats, because tomatoes need soil temps above 70 for germination. After they are well started you could bring them out to your greenhouse if night time temps in it are reliably staying above 40 deg. You do need a min-max thermometer that records what the temp got down to.

8" of soil is very minimum to grow tomatoes in, over concrete. I think you would be much better off to make it 12". And do be sure about the drainage. And then think 5- 6 plants, not 7, with some smaller stuff around the edges.

Your greenhouse has only one roof vent, which doesn't make for any flow through ventilation. You will need to get one of those automatic thermostat controlled openers. Even on very cold days, if it is bright and sunny, your greenhouse can heat up intensely during the day and cook your plants. Were you planning to leave them in the greenhouse through the summer? Then you will need the door open and fans circulating the air and may need shade cloth or something over some of the windows to keep it from heating up too much.

You can grow almost anything in containers if you set your mind to it and have big enough containers. If you are using smaller containers, like about 2 gallon size, then you will need plants that stay smaller. Peppers are ideal for this and a variety of herbs like basil, sage, rosemary, oregano, parsley, etc. Greens, like lettuce, cabbage, spinach, chard are good for containers.

Best wishes and keep asking questions as you go along! Welcome to the forum!

[tomc]

Are these double pain panels!?

The advert says single wall poly carbonate. A second "R" can be fabricated with a clear plastic drop cloth.

I think if he's facing 30F night time temperatures, um er if it was my toy I'd want twin-wall poly carbonate (clear) panels.

I did not check to see if it came with automatic top vents. He wants those too.

As far as space goes a few full sized tomato plants and space to start others early will fit into a six-by-nine green house. For the american family of 2 adults and 2.3 children thats about what I'd want.

You may be, no you will be supplimenting heat with warm blooded plants like tomato and pepper in your climate.

Enjoy this new gardening time. Its a blast.

[Bobberman]

This may sound stupid but you could get a 6 mil clear plastic and put it over your green house for the cold weather so it makes a double layer. Another option would ne a 4 mill inside the greenhouse taped in or stappled to wood slats. its a cheap way to go. $7.00 at big lots for a 10 by 25 4 mil! This would keep your greenhouse above 30 probably all winter without any heat just like mine! I keep flowers in it all winter from the fall before! They make a whats called a personal heater at Wal Mart $12 that is only 250 watts that I use sometimes in a heat chamber. I simply hook it to a timer and have it come on for a half hour every other hour at night when I start my seeds! You have a small greenhouse and that little heater will raise the temp I bet 10 degrees! The single layer does not compare to the double layer! I would put it in the inside if you can its pretty simple. Even a 3 mill will work inside since the weather will not effect it! You may even be able to use squeeze clips to hold the plastic inside or maybe a good tape!You weather is a little warmer than mine since you are close to Vir.!