Make the Most Out of Your Mini Greenhouse

Reader Contribution by Mari Stuart and Carbon Harvest
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Photo by Annie Spratt on Unsplash
 

A mini greenhouse creates endless new possibilities for the home gardener. It extends the growing season and provides a protected space for more tender plants during the winter months. Even a simple, unheated greenhouse keeps the temperature about 10 degrees F warmer than outside. Depending on your growing zone, that could mean salad greens and kale all winter long, or extra-early carrots or strawberries in the spring — or even being able to grow semi-tropical and tropical fruits such as citrus, avocado, or olives.

Mini greenhouses come in a few standard sizes, such as 6×8 feet or 6×10 feet. That may not seem like a lot of space, but by strategically planning the layout, you can maximize the efficiency of the space and what you get out of your greenhouse.

Here are some design principles for creating the layout of your greenhouse:

  • think versatile
  • think vertical
  • think seasonal
  • plan for how you will be using the space

Think Versatility

The way you use the greenhouse will change from season to season. Set yourself up for success by creating a few different zones or areas that you can adapt to multiple uses.

You need to leave space in the middle for a pathway (minimum 1.5 ft wide), so you really can only use the space in a U-shaped area along the edges and at the end for growing. One approach would be to fill up this U-shaped area with either raised bed boxes or fixed shelving. My recommendation, though, would be to set up a couple of different types of areas.

If you create a raised bed box on one side and create gravel flooring for the rest, that gravel area can be changed and adapted based on your needs. (Gravel flooring is ideal because it keeps the space tidier than a dirt floor would be, and the rocks store heat during the day and release it during the night, keeping the space warmer during those critical spring nights.)

You could set up shelving for seedlings and potted plants in the spring, replace them with large self-watering containers for tomatoes and peppers in the summer, and use the space for potted subtropical plants such as dwarf olive or citrus in the winter. You could even set up a potting table, with compost and soil stored conveniently underneath, for part of the season.

Think Vertically

The footprint of a mini greenhouse is small. Solution: grow vertically! Stacking crops vertically allows you to make the most of the sunlight and space all the way up to the ceiling.

You can use hooks or top shelves, or hang containers, such as baskets of strawberries, from the ceiling. If you have an aluminum greenhouse, you should be able to find fittings and hooks specifically designed to fit the frame. With the help of hooks and garden twine, or tomato cages, you can trellis plants such as pea vines, tomatoes, and cucumbers to grow up. You can also use the ceiling space for drying herbs or hanging your gardening hand tools.

Shelving is another great way to make full use of the height of your greenhouse. You can choose between free-standing shelves and wall-mounted shelves specifically designed to attach to the frame. Adjustable shelves are ideal. Though many gardeners prefer wood as a material, remember that insects and pests can overwinter in wood – plastic or metal may be the better option.

Think Seasonality

The “landscape” of your greenhouse changes as the seasons change. Reserve the precious real estate of the greenhouse for plants and purposes that really need or benefit from that extra protection and warmth.

In the winter, depending on your growing zone, the greenhouse might be the one place where you can still grow year-round salad greens, or Brassica greens like kale or tatsoi for braising and steaming.

In the spring, starting an extra early crop of sweet peas or strawberries in the greenhouse makes for a lovely treat in March or April, a few weeks before peas or strawberries will start producing outside.

In the summer, reserve the greenhouse for heat-loving plants such as tomatoes, cucumbers, eggplants, or peppers. Plant vegetables that don’t particularly need the heat elsewhere. The same goes for vining vegetables that take up a lot of space, such as melons and cantaloupes; growing them in a mini-greenhouse simply isn’t a good use of space.

Summer vines in the greenhouse 

Plan for How You Will Use the Space

­­I’ve made the mistake of planting the entire greenhouse so full that, by July, I had trouble even entering. The greenhouse was one shiny box of jungle, with tomato and cucumber vines sprawling out the door and the vent. It was exciting, though not exactly convenient, to try to enter and harvest food.

Remember: if it’s hard for you to get in, you won’t be very successful at keeping an eye on your crops! Design space for yourself.

Think about how you will be using the space, and design enough space for those activities. Definitely leave enough space for that walkway in the middle. If you want to do potting inside the greenhouse, reserve one corner for a potting table. Trellis and train your most vigorous plants so as to guide their growth enough that you can still access the very back of the greenhouse.

The drawings below show possible layouts for a standard 8×6 ft mini greenhouse through the four seasons.

Spring

  • bring in racks or shelving for seedling trays
  • cover crop is mowed down and different brassicas, lettuces, and peas are planted in
  • harvest carrots and salad greens from smaller containers
  • start an early crop of strawberries in hanging baskets

 

Greenhouse spring layout 

Summer

  • spring plants have given way to heat-loving summer vegetables: cucumber, eggplant, pepper, and tomatoes
  • you can plant several cucumber and tomato plants in the raised bed box and grow smaller, more compact peppers and eggplants in containers

 Greenhouse summer layout

Fall

  • keep harvesting the last of summer tomatoes, peppers, and eggplants well into October
  • then clear out any plant debris, spread a fresh layer of compost, and plant a winter cover crop or winter veggies that are not heavy feeders, such as lettuce
  • plant winter salad greens in containers
  • bring in any potted dwarf subtropical plants, such as citrus, avocado, or olive to overwinter in the greenhouse

 Greenhouse fall layout

Winter

  • plant winter Brassicas, such as kale, broccoli, or collards in the raised bed
  • keep harvesting salad greens from smaller containers
  • check on overwintering potted plants

 Greenhouse winter layout


Mari Stuartlives in Asheville, N.C., where she stewards an urban homestead with her husband and daughter. She is a project designer for Carbon Harvest, a pioneering community-powered carbon farming initiative in Southern Appalachia, as well as an edible landscape designer, homesteading skills teacher, and freelance writer. Connect with Mari at Make Gather Growand its FacebookandInstagram, and at Carbon Harvestand itsFacebookandInstagram. Read all of Mari’s MOTHER EARTH NEWSposts here.


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