Mini Greenhouse – Stretch your Growing Season


Mini Greenhouse – Stretch your Growing Season

Mini Greenhouse - Stretch your Growing SeasonMini Greenhouse – Stretch your Growing Season

With this mini greenhouse, we enjoy greens and fresh salad all winter long. Learn how we built our hoop house with scrap PVC, a strip of 6 mil plastic, and a few PVC fittings, for less than $20.

When winter is coming on here at our Arizona desert homestead and the temperatures are dropping, we still look forward to eating fresh kale, chard, escarole, lettuce, and other fresh hardy produce with the aid of a mini greenhouse. Don’t be misled by the fact that our homestead is in the southern Arizona desert. Last year, one storm dropped six inches of snow on our place. The following week, another cold front brought our temperatures here at the Bear Cave down to 2⁰F. It gets more than cold enough here to zap most tender growing garden plants unless we provide some protection.

Last year, we simply protected as well as we could with row cover. We found that without supports, heavy frost and snow broke down some of the plants under the row cover. While it probably didn’t hurt the nutritional value when we used them immediately, we really felt sad about the squashed greens. They looked pretty pathetic.

So this year, we decided to give them another layer of protection. Our neighbor had done some plumbing in a new out-building and had left a small pile of scrap 3/4″ PVC out behind his shop. Our Arizona sun had baked the pieces for a number of months and they were definitely too brittle to make a hoop. Enter the PVC angled joints. With a pair of 45⁰ and one 90⁰ couple, we had our own version of a hoop for our mini-greenhouse. By repeating this process five times, we had five supports for our mini greenhouse.

Our expert (among so many other things), drew out a plan using the width of our raised bed as the length of the hypotenuse of the isosceles triangle that became the top section of our “hoop”.

This calculation gave me a very accurate measurement for the length of the angled “hoop” sections. This resulted in the top sections of PVC being cut to 31” based on the 43” outside width of the raised bed. We determined the rise of the “hoop” by estimating the height of the greens at the edge of the raised bed. In our case, we made the side pieces 14” high.

We assembled five of these hoops to give us a mini-greenhouse with supports every 2 ½’. We dry-fit the joints for convenient disassembly and storage next summer.

We drove pieces of 3/8” rebar into the ground at the outer edge of the bed and slipped the end of the PVC hoop over it. We then tied the PVC hoop to the raised bed with plumbers tape and a couple of short sheetrock screws. Besides allowing us to level the tops, this seems to support the hoops well with both the weight of the plastic cover and some wind attempting to move them around.

Mini Greenhouse

Two sections of light cotton line tied with the ends out on one side and in on the other made a system that allows us to tie up either one side or both sides for picking produce or working in the garden.

In high winds, you will want to weight down the edges of the plastic to prevent flapping.

Two sections of light cotton line tied with the ends out on one side and in on the other made a system that allows us to tie up either one side or both sides for picking produce or working in the garden.

In high winds, you will want to weight down the edges of the plastic to prevent flapping.

In the event that you have to buy your PVC new, this little Mini Greenhouse will still be both practical and inexpensive.

An all Year-Round Maintenance Greenhouse

Each season requires specific maintenance :

  • Spring is a busy time in the greenhouse. You can take out the plants that can now grow outdoors and prepare the blocks for sowing. It is important to ventilate the place at this time.
  • In summer, the plants must be protected from burning. Either cover the windows with a coat of calcium carbonate or install awnings to reduce the sunlight by 40%.
  • Water the plants heavily in the cool of the evening.
  • The greenhouse can be ventilated by leaving the door and the windows open. This will also stop the rot and damaging insects from proliferating.
  • As we have mentioned, autumn is the time to give the greenhouse a thorough cleaning.
  • In winter, if the greenhouse is heated, check the heating and temperature periodically.  Ventilate from time to time.

Greenhouse terms

People who live in glass houses should know these words


Glazing, the same as any that might be applied to your home windows, helps keep warm rays from escaping once they enter. Unlike in your home, a greenhouse glazing may be somewhat opaque and thick, to greatly increase the temperature without concern for visibility.

Vent Control

There are several products available that vent your greenhouse. Of course, simply opening the door when things get a little too hot is acceptable, but there are options. A solar-powered vent control can be set to one-degree increments, opening a door, roof, or wall vents. This way you don’t have to worry about your greenhouse overheating.

Seedling Heat Mat

To get the young guys going, sometimes it’s necessary to provide a little help. A heat mat gives radiant heat to the roots of young plants, about 10 degrees higher than the ambient temperature.


You’ll need a decent set of lights to make your greenhouse worth the effort. We suggest reflective aluminum inserts, a mounting system, and individual on/off switches. Other things you may want to consider are built-in ballasts and glass lenses.

Watering Systems

Greenhouse watering systems are plentiful and varied. The handier ones operate on gravity and are self-filling. Some greenhouse kits have a combined watering/fertilizer unit.

Greenhouse Misting

Misting your greenhouse is a reliable way to maintain the temperature cool and safe for your plants. A good greenhouse misting kit can lower the temperature by as much as 25 degrees F. Misters also provide greenhouse humidification at the optimal levels, around 50-70%. Make it easy on yourself and get one that connects to a hose or outside faucet.

Greenhouse Heater

Most gardeners simply use a portable space heater. About 25-30% of your heat can be acquired from the sun, and a properly insulated greenhouse will keep warm enough. Some gardeners use solar power to operate their heaters and save on costs, but this is a fickle source and should always have something reliable on backup.

Greenhouse Kit

This general term describes a number of packages that you can buy to get you started. Some will have all you need, and others will be simply a frame and your greenhouse panels. Even larger greenhouses are sold as kits, not just the portable or mini-greenhouses. These will save you time and money, along with giving you the comfort of having a phone number to call in case things get tricky for you.

You can enjoy a longer growing season and happy GARDENING

Follow us on: TwitterFacebookPinterestInstagram

Gardens nursery Store

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.