Cheaper temporary greenhouses - worth it?

[Dimples]

We’re renting so spending a lot of money on a greenhouse isn’t in the cards at the moment, but I’m curious about this pop up style. Anybody using one of these now, or prior?

If I’m careful to set it up correctly so it’ll withstand our windy conditions without blowing over, be careful with the plastic (etc.), and put it away for 3-6 months a year, how many seasons could I expect to get out of it before it’s so trashed that there’s not enough tape in the world to fix it? Two or three?

Our summer and fall sun can be brutal but the greenhouse will be mostly shaded by the house in the late afternoon.

[estación seca]

Your main problem will be wind, not only blowing over, but also the fabric rubbing against the frame. If you calculate the force of 50mph Santa Ana winds on the covered frame you'll probably find out the stake hold-downs are not enough.

They don't explicitly say what is the material but I'm guessing PE means polyethylene. I would contact them and ask how long it lasts in the sun, plus what percent of light is transmitted. You might still need shade cloth over it, or you might not. Also ask whether replacement covers are available.

[Dimples]

Asking about replacement covers is a great tip. Thank you.

Whatever I get will be on a paver patio, so it will be sandbags, gravel, etc., weighing it down. I will probably bolt the feet to 2x4s to provide more area for laying weights.

Cover corners and rub points will be reinforced and it will be tucked into an indented corner on the leeward side of the house, so only one partial wall will be in the direct path of wind.

I am planning on adding shade cloth. From reading, the light passage for white-reinforced clear PE is higher than the green-reinforced, but I’d rather have to add shade.

[Roberta]

Question... do you really need a GH in summer/fall? I can see where it would be beneficial for warmer-growing orchids in winter if you don't want to bring them into the house. Then sun won't be such a problem in terms of attacking the cover because sun angle is lower. In the warmer months, I would expect that essentially everything would be quite happy outside under some shadecloth. (Take a look at my website to see the "structures" that I have, build out of metal conduit, to hold up shadecloth) Even now, with the June gloom, temps are warm enough even for warmer-growing orchids like Phals. You won't need to protect from cold until late October. But in summer, your problem with any sort of enclosed space (with sides) is going to be heat.

[ArronOB]

I can’t see your link but I’ll answer from my own experiences.

I had to rely on 3 of these for a couple of years and honestly they were a lot of trouble and cost me a lot of plants:

EAGLE PEAK 61'' x 28'' x 79'' Walk-in Greenhouse, 2 Tier 4 Shelves Portable Plant Gardening Greenhouse, Front Roll-Up Zipper Entry Door and 2 Roll-Up Side Windows, Green : Amazon.com.au: Garden

Wind was a constant problem. I came home a few times to find one blown over and plants, pots and media in a foot high stack on the ground. After I sorted that out so they were firmly fixed to posts driven into the ground it helped but didn’t solve the problem. Even when well fixed down the upper part would still move around in the wind and the stupid springy shelves would flex about bouncing the plants over or even right off the shelves.

A worse problem was heat. I don’t think our climate is nearly as hot or unpredictable as yours but I still got a lot of heat damaged plants. My intention was to use the supplied plastic covers for the coldest 3 months of the year, and a sewn on home-made shadecloth covers for the warmer months. The problem is if you get an unseasonal hot day in winter then everything inside cooks, especially if you’re not home to open the flap/door up and splash water around. One winter day we had to drive down to Sydney and the weather changed becoming very warm so I had to ring around the neighbours till I found someone at home who could go to our place and take care of it for me - still lost plants.

In our climate these things lasted 2 or 3 years. The first things to go are the zippers, followed by the lowest joints in the framework which are just plastic coated steel and very rust prone where water might sit. The actual plastic covers are very tough and will last for many years (as landfill).

Outside of the three months of winter, my intention was to remove the plastic covers and sew on a close cover of shadecloth all over. You couldn’t use the plastic covers on a day of over, say, 25degrees celsius or you’ll get cooked plants as they are not designed for airflow. Shadecloth is not easy to sew so that was a lot of work that I wouldn’t do it again. I even tried making slip-over one-piece shadecloth covers on an industrial sewing machine but getting the sizes and angles right did my head in.

Another thing to remember is they provide almost no protection from cold in winter. If the temperature has fallen to 10degreesC outside then the inside will be the same temperature within a fairly short space of time. Thin plastic provides no worthwhile insulation.

So no, I wouldn’t use them again.

If I was in that position again I’d buy some framing timber (2x4 or 2x3) and some shadecloth and make something very simple of my own design. Perhaps a lean-too style that uses a house wall for one side, leans up against it. Build the shelving so it’s free standing and not troubled by the framework thrashing around in the wind. Make things modular so they can be moved and reconfigured and used somewhere else if need be. Take it with you when you cease renting.

Also, why do you need a greenhouse in San Diego anyway? I thought it was warm there year-round?

[WaterWitchin]

I'm with Roberta and Aaron... Isn't your climate similar to a greenhouse anyway?

What is your rationale for wanting a greenhouse?

[Dimples]

We’re inland enough that our expected nighttime lows are in the 50s for most of the year. July-September is the only time we can expect consistently warmer overnight temperatures in the 60s. I’d like to move some of my larger tropical houseplants outside so I can heavily prune them for some reshaping that we don’t have enough light for inside. While the daytime is pleasant year round, I would have to move a lot of large plants in and out every day in the early and late season if I don’t have a greenhouse type structure to moderate temperatures.

With the current gloomy weather, we’ve been in the low to mid 60s when we should be 10° higher. So, while I don’t explicitly need a greenhouse, I can’t do what I need to do without one.

If anyone has any other ideas, I’d love to hear them.

[estación seca]

Most orchids and tropical house plants would be fine with night lows like that most of the year, especially in summer when days are much warmer. Exceptions will be most Phals and Vandas.

[Roberta]

I think just patience... summer warming is running late this year, but we'll be seeing those mid 60's F nights within a month or so. By the time you get that GH you won't need it. What you can do is put those more fragile plants outside, but next to the house or if you have it, a block wall. You'll get a slightly warmer "mini-micro" climate due to warming during the day, where the wall radiates heat during the night. A couple of degrees is all you need for safety. That, plus the fact that the nights are shorter (so plants experience chill for fewer hours) will likely give you the conditions that you need.

[Leafmite]

Living here in Ohio, cold is something I understand. Temps in the fifties are fine for all the orchids. I get that many nights during the summer and every plant is outside. Even the hot growing Phals will be okay with those temperatures as they are only for a couple of hours.

We are going to have temps in the upper forties in the upcoming week and I will only bring in the vanilla orchid...the rest should be fine for a couple of hours at that temperature.

This post is the type that makes me envious....