Mini Greenhouse questions

[Parasocks]

Hi All,

First-time poster, long time lurker.

I recently saw this mini greenhouse and was thinking about purchasing it. Not sure if anyone has experience with something like this and if you would recommend it. It will be used mainly for orchids. I did see it this weekend and it seems fairly solid. Its ~$100
Walk In Grow Tent (1430 x 1430 x 1950mm) | Planting & Soil Preparation | Fertilizers & Plant Food | Garden | Garden & Outdoor Living | Builders South Africa

I have a number of different orchids mainly Phals, dendrobiums, oncidiums. I am based in JHB, so it is pretty dry here around 50% humidity here. I will keep this outdoors. We usually get clear blue skies in winter so light should not be an issue, temperatures are usually just above freezing at nights in winter and mid-teens duirng the day. I was thinking of installing a few small USB fans for some airflow.

Not sure if anyone has any opinions on it, or any advice on mods that i will need to add.

Thanks
Parasocks

[Dollythehun]

I've purchased two of those this year. They're pretty sturdy and we'll made for the price. At just above freezing, you may have to put in a small heater, like a Honeywell "Heatbud." We are in very different climates, so I'm not much help but, it was a good purchase for me.

[mildwhiskers]

I just got this one for Christmas, I'd also like to hear some advice on what utilities to get for it, as it is my first greenhouse.
I will say though that if you have strong winds where you plan on putting it, make sure you put some extra weight on the shelves. Where I had mine set up I couldn't pin it down with the guylines it came with, and so one very windy night a couple weeks ago, it went flying across the yard. Thankfully I hadn't moved any plants inside yet and the greenhouse is still intact, just a bit scratched up. But having just plants on the shelves, even with the guylines in place, won't be enough for holding it down in strong winds.

But overall I like that it's portable, so when it gets too sunny and hot, I can move it to a shadier location and vice versa during winter. Other than that, I'm still researching what to get for heating and humidity before moving my plants in.

[Roberta]

Parasocks -

I think you will want to add a small heater, especially for the Phals. Without heat, it will go down to ambient outdoor temperatures, Phals especially you'd want night temperatures above about 12 deg C if you can manage it. Fans to facilitate air movement are certainly a good idea. During spring and summer, you should be able to move everything outside (with a bit of shade) - you can compensate for low humidity just by watering more.

Mildwhiskers -
I'm glad the greenhouse survived being blown around the yard. Yes, wind is a big issue. Along with the guylines, is there a way to use bricks or cinder blocks for weight? You can also move things outside during the warmer months.

For both of you... summer sun can make the inside of any greenhouse very hot. If possible, just move the plants outside once night temperatures are above about 55 deg F/12 deg C, Mother Nature provides the best airflow!

[Merita]

I had it, under a big shadow it works well, if the sun goes down somewhere in the summer, the plants are cooked. This is here in Florida, I don't know if your summers are mild.

[Roberta]

Originally Posted by Merita

I had it, under a big shadow it works well, if the sun goes down somewhere in the summer, the plants are cooked. This is here in Florida, I don't know if your summers are mild.

Merita -
Parasocks lives in the area of Johannesburg, South Africa and Mildwhiskers lives in the east San Francisco Bay area of California USA. (Climate in these locations at opposite sides of the world are quite similar) Both can have rather hot summers... that was why I noted that in summer, a greenhouse like this can get very hot, and the plants are likely to be better off outside. In the cold months of the year those mini-greenhouses can be very useful in both locations, where bad frost is rare but winter nights are cold enough for orchids to need some protection.

[ArronOB]

I have two like that but a bit smaller, and one about quarter the size. We are just north of Sydney, climate like this Climate statistics for Australian locations , or maybe a degree or two warmer in winter.

Main issues I found were
The covering is some type of plastic which doesn’t breath. A hot day in early spring was enough to cook several of my plants. Now i have taken the original covers off and fixed shade cloth all over. I put the covers back on for the coldest three months of winter. Even in winter I have to keep the doors open (rolled up) during the day to stop the heat buildup. In other words, I’m always working hard to manage the temperature.

On winter nights the temperature inside equals the temperature outside fairly soon after sunset. There really is no heat retention through the night that I can see.

On several occasions I have had the shadecloth door flop open and this has led to sunburn.

As already mentioned, they are very vulnerable to wind. Mine are against walls so aren’t really going to blow anywhere, but when it gets windy they shake about and because the thin wire mesh benches act like trampolines then I can guarantee there will be plants knocked off the shelves on a windy night. Mine are held down with old diving weights.

They are also very flimsy, especially the seams and zippers. I bought mine very cheaply, but if that weren’t the case then I would have been much better off buying/scavenging some construction-grade timber and some rolls of shadecloth and building something of my own design.

So no, I don’t think they would be a very suitable growing environment for JHB. I think your location would be both hotter and colder then ours, and what they don’t do well is extremes.

I use them because I have too, due to limited space and need for mobility. I grow mainly Oncidium hybrids and cattleya hybrids and species. I also have a few phals and Bulbophyllums . The phals and bulbos come inside for winter, the rest are in the shadehouses year-round.

I also have a fixed, timber-framed shadehouse built by the previous owner. Although it is of an odd design and only part of it is usable for orchids, growing in it is a breeze in comparison.

Cheers
Arron

[SouthPark]

I have heard of growers tell of events just as Arron described involving windy conditions. Strong winds can take down this type of mini greenhouse. Eg. a storm. If a region does get gale force winds .... then a stronger structure could be considered - if feasible that is.

[Merita]

Originally Posted by Roberta

Merita -
Parasocks lives in the area of Johannesburg, South Africa and Mildwhiskers lives in the east San Francisco Bay area of California USA. (Climate in these locations at opposite sides of the world are quite similar) Both can have rather hot summers... that was why I noted that in summer, a greenhouse like this can get very hot, and the plants are likely to be better off outside. In the cold months of the year those mini-greenhouses can be very useful in both locations, where bad frost is rare but winter nights are cold enough for orchids to need some protection.

I had it and it worked well in the winter, covering it on very cold nights; in the summer under the big shadow of a tree, I left it open and it worked well but I cut some branches to the tree, which were directed towards the roof of the house, and began to warm up, I covered it with cloth and it didn't work , not to tire, I ended up moving the almost cooked phals to the porch of the house. Really if I had a big shadow I would buy another one because the time I had no problems with the sun, it was very good for the phals.

---------- Post added at 10:52 AM ---------- Previous post was at 10:38 AM ----------

Originally Posted by SouthPark

I have heard of growers tell of events just as Arron described involving windy conditions. Strong winds can take down this type of mini greenhouse. Eg. a storm. If a region does get gale force winds .... then a stronger structure could be considered - if feasible that is.

It is necessary to stake it well by the winds, which the greehouse brings, they are not very strong but in Lowes they are bought bigger. The first one I had, a cyclone broke it, nothing can be done there, the second one I bought was useful until the sun affected me. They are very good under trees, with shadows.

[mildwhiskers]

Originally Posted by Roberta

I'm glad the greenhouse survived being blown around the yard. Yes, wind is a big issue. Along with the guylines, is there a way to use bricks or cinder blocks for weight?

Yeah, I put bricks on all of the lower shelves to keep the greenhouse grounded. It hasn't budged since, so something heavy that can fit on the lower shelves seems to work fine.

I have also noticed the same issues with temperature that ArronOB had in that the greenhouse being hit with direct sun, even now in January, heats the inside anywhere from 75°-90°F/23°-32°C. It also drops to the same temperature as outside at night, which have been pretty cold here. It even dropped to 28°F/-2°C once, so I have been very reluctant to move the plants in, at least until I can set it up so they don't burn or freeze to death.

Also the humidity goes up to 98-99% at night but by around 9 to 10 AM it drops to 25-35%. So a humidifier or something may also be needed for during the day.

This greenhouse is really my only option for moving most of my collection that currently lives in my room outside. I have some plants outside but they're isn't much space available that isn't exposed to full sun and extreme temperatures. And the conditions in my room aren't the best for them, so getting this greenhouse up and running would really make them a lot happier I think. After doing some digging on the web, I haven't been able to find much advice for using or setting up these smaller greenhouses in general, so hopefully you all might be able to bring some insight on that.