Going into the cooler season now, I would like to build a greenhouse. Am wanting some advice on what plants are best grown in a greenhouse over winter? Am I able to plant anything year round if grown indoors? (Sorry, novice gardener here).
A have also been looking into DIY greenhouses as would like to keep costs down.
Harbor Freight has reasonable prices on small greenhouses--got both sizes. I tried several other types first which proved to be mostly wasted money. Depending on how handy you are, you could build one from wood & cover it with plastic.
Before any advise can be given it would help to know what growing zone you are in. Also, will you heat the greenhouse to keep the temp 60 degrees or more. Lower temps than that will not promote growth. What do you want to grow, tropicals flowering plants, vegetable, etc. What size are you thinking of.?
If you plan on using the greenhouse during the summer, you will need a cooling system rated to the inside air space of the greenhouse.
During the 80's, I owned and operated a commercial greenhouse built by my husband from my plans. I did a lot of research prior to making the plan. My greenhouse was solid from groundlevel to 3ft since I had no intention of using the space under benches. The frame was redwood to prevent rot from moisture. The rest was fiberglass. I had 2 heater hanging and 2 24" fans. One blew air through water at groundlevel. Acted like a swamp cooler. I also used shade cloth in some parts of the greenhouse for shade loving plants during the summer.
Most greenhouse kits are made by people who don't know anything about greenhouse growing. I started with a 6ft x 8 ft greenhouse kit. My daughter just purchased a greenhouse from Harbor Freight. They just finished putting it up. That is when you see that pieces don't all fit, and it is not meant for high wind areas. Too flimsy. My son-in-law had to figure out how to get around that for sturdiness. She wanted it just for starting plants during early spring, and to extend tomato season in the fall. No tip on how to install a heater or fan. There are 2 opening on both side of the roof, but they do nothing to cool inside. It is corrugated plastic.
If you can build your own from a plan, you will get a better item. I read your link and it asked the same that I did---what will you use it for. Since you intend to use it in the winter, you will need double insulated fiberglass. My daughter's greenhouse is made of corrugated fiberglass. Ofcourse, it depends on where you live.
Whatever greenhouse you build or buy, it is important to aim it north and south lenghtwise. The reason is that the sun goes from east to west on the greenhouse and placing the greenhouse as mentioned prevents hot spots that would happen if it shined on the long side of a greenhouse all day.
Google "greenhouse growing" and you will most likely find information. I wish I had digital photos of my greenhouse but no such thing in the 80's.
If any greenhouse kit could be recommended, it is one using Solexx greenhouse covering. The idea originated in Germany. I got the information online. I was going to buy a small greenhouse for starting plants that I sell, but nixed the idea for lack of space.
No, Harbor Freight sells twin-wall polycarbonate greenhouses--not plastic. I sealed mine with silicone, situated it to be partially shaded & catch prevailing winds in the summer, have 350 gallons of water in black barrels for solar gain in the winter plus a small electric heater which is rarely used . Granted, I am in south Texas, but last winter we had 10 degree days in a row and lots of triple digits this summer.
Where you are and how you plan to use it are the bottom line--nothing is written in stone, believe me. For really cheap & easy, check out eBay. I am considering adding one 10x20 that's like a quonset hut (poly tunnel) for under $150. Again, there is no "only" way except in someone elses mind.
Polycarbonate is a type of plastic. The Solexx greenhouse coverings are polyethylene which is another type of plastic. I agree on sealing with silicone--my GH isn't Harbor Freight but it's probably similar quality construction (twinwall polycarbonate panels) and after I'd had a couple panels blow out in the wind I caulked around all the edges where the panels go into the frame and it's held together perfectly (through 2 winters of wind storms) since then.
Over here in UK, the Polycarbonate goes brittle with weathers different Temp's and needs replaced as it cracks, I have a large greenhouse and it is set at the roof ridge Angle of North south to catch as much winter light as possible, I save my bedding Fuchsias and bedding Geraniums etc in the greenhouse over winter, bring on cuttings, grow seeds, early start some types of veg, save things like Angels Trumpet and lots of other plants that are hardy to some USA zones but very tender to us here in UK.
My greenhouse is stone walls up to about 4 feet, concrete flooring and above the walls is Clear Glass on three walls (mine is Leanto) this gives me extra winter protection and the house warms up earlier from the wall early spring saving me heating.
Depending on what you want to grow and your zone as mentioned, there are plenty ways to protect tender plants like covering the trays / pots with horticultural fleece, this keeps the plants from air frost, there are heaters for trays on the benches, there are heaters for wall mounting either paraffin, gas or electric, there a fans for summer and some heaters go reverse and are cool blowers in summer as well as heat in winter so there are lots of things to use and cost is something as individual as the greenhouses themselves.
My advice is, buy or build The biggest you can manage at the offset as you will be surprised at how fast you can fill a greenhouse, make sure you get electrics and water run to the greenhouse as this saves back breaking carrying, use water butt's if possible and set electric on timers so you don't waist money, either building or buying, make sure you get as many roof vents as possible and add some temp controlled roof vent fittings, these open / close if you are out, use hard woods if possible and every 2 years make sure you paint the wood preserve to the window ledges doors etc as you are using lots of water inside and out which sends out condensation in winter.
I could go on more but to be honest, the best advice is go to library for books on greenhouse growing, what equipment you need for basics, the rest is choice of equipment, after that reading exercise, ask a woodworker to cost the full package you need once you have sizes / plans and go from there, I have never seen a good substantial greenhouse made from plastic in our climate so again you need to consider where you live, your summer, winter temps etc. but a good hand book on greenhouses will tell you all this. Lastly as there are no cheep greenhouses worth there money as over a few years you have to replace them so if possible, make this your winter project and get ready for spring building, if you go ahead now without the proper knowledge of what a greenhouse entails then you may end up with an un-usable expensive pile you don't enjoy using or how to care for the plants within.
hope all this and others help is taken and you go about it the right way, I have seen some lovely empty greenhouses left to rot as they are the wrong choice for that person and they don't understand the way a greenhouse works.
Good luck, WeeNel.