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Freestanding Greenhouses for All Plants

For starting greenhouse plants, Tricia enjoys starting with a variety of seeds. These seeds go in her outdoor flower and vegetable gardens.

Interior view of a simple constructed standing greenhouse.  Learn the purpose of a greenhouse.

Interior view of a simple constructed standing greenhouse. Learn the purpose of a greenhouse.

Function of a Greenhouse

The sole purpose of a greenhouse is to grow plants in a protective environment. The exterior of the greenhouse may be plain or decorative. The interior is organized with shelves and hangers for a variety of plants. Both the exterior and the interior is custom-built to meet the owner’s requirements.

This is a multi-purpose building for growing, storing, and experimenting with a variety of plants. Hobbyists and commercial growers favor these buildings. The interior environment controls temperature, water, and air favorable for ultimate growth, while the exterior construction provides protection from the elements.

Other benefits include:

  • No pests: control the interior environment, avoiding pesky bugs plus other irritants.
  • No heavy tools.
  • Plants grow throughout the year.
  • Allergy-free plants, tropical foliage, and other specialty specimens can be grown.

Location and Costs

Land space will decide the size of a free-standing building. It needs to meet hobby or business use. Hobbyist use their available residential space. The backyard is a popular location. Commercial growers invest in large land tracts appropriated to their horticulture interests

We grow a variety of orchids for personal use. We thought one building would be sufficient, however; the orchids have propagated, demanding more room. Thank goodness we allowed for building expansion. This is not unusual. We know several people who preferred their love of plants to be a hobby. Their hobby became a part-time or a full-time business.

What are the costs of a greenhouse? The estimates range from $3500 to $18,000 in residential locations. Are you a handyperson? You may decrease these costs from 25 to 50 percent less by putting up the building yourself.

Maintenance expenses include heat, air conditioning, solar panels, exhaust fans, vents, insulation, watering systems, plus electricity. Each local government has rules and regulations governing greenhouse construction. Inquire about zoning, building permits, and other requirements. Failure to satisfy your legal responsibilities may lead to a hefty fine along with removal of the structure.

Miscellaneous costs include shelving, hanging plant structures, storage bins, work bench with stool, hand gardening tools, various planting pots, and minor items such as identification labels.

Polycarbonate greenhouse kit to assemble

Polycarbonate greenhouse kit to assemble

Basic Freestanding Greenhouse

We can purchase greenhouses, pay a building contractor, or turn it into a do-it-yourself project.

A basic freestanding greenhouse is an oblong box with two sloped roofs and a ridge. The ridge is metal or wood one-piece structure placed at the highest point of the sloped roof. The type of plants will verify if the ridge is to be a simple strip or a ridge-vent style, which relieves the greenhouse of warm, moist air.

  • Screened windows, fans, and vents will allow circulation of fresh air.
  • Eaves (roof overhang) will be any length you want. These help keep water away from windows and interior walls.
  • Flooring may be the land itself, pebbles, concrete base, brick, or wood. The climate will determine window types, insulation, and screening.
  • Windows may be glass (avoid direct sunlight), screen, or polythene sheets (plastic film). Window materials depend on the building’s location and climate.
  • Red cedar wood, aluminum, brick, plastic, plus concrete are choice construction materials for these structures. Your choice is based on personal preference and which material offers the best solution.
  • We may use wood stain or paint to protect and color coordinate with other remaining buildings on the property.

It has been our experience that wood seems to be the best material. It adds beauty and value to the landscaping. It allows greater freedom in creating shelving, work table, storage bins, and assorted aids for potted or hanging plants. It is also easier to make repairs, additions, and have lower maintenance costs. Metal and concrete have their limitations, and costs are higher when making changes or repairs.

A small polyurethane garden greenhouse suitable for a home gardener or hobbyist.

A small polyurethane garden greenhouse suitable for a home gardener or hobbyist.

Size and Maintenance

Measure the land on which the free-standing structure will occupy. Observe the area around the building placement allowing space for the height, extra spacing around the building for plant accessories, storage shelving, and expansion. As a hobby, the land space becomes the border for the number of plants. What will you do when the plant quantities exceed the size of the greenhouse?

List of maintenance expenses:

  • Heat and ventilation appliances or systems
  • Solar panels or electrical
  • Exhaust fans
  • Vents
  • Watering systems
  • Zoning, building permits, and other legal requirements
A small greenhouse in a private garden of Australia.

A small greenhouse in a private garden of Australia.

Greenhouse Tips

  1. Build a larger structure than what you think you need.
  2. Provide a cool frame for planting seeds.
  3. Regulate light, heat, and moisture.
  4. Use six hours of natural light per day.
  5. Use artificial lighting when necessary.
  6. Keep indoor temperature settings at 80–85°F.
  7. Maintain humidity at 45–50%
  8. Ensure ventilation to prevent moisture buildup. Leaves start producing moisture at 59°F.
Green lettuce growing in a mini-greenhouse.

Green lettuce growing in a mini-greenhouse.

Edible and Ornamental Plants

Many seeds from fruits, flowers, vegetables, herbs, and trees will thrive in a greenhouse. Depending on the plant variety, it may require transplanting outdoors to continue its growth in a natural environment.

The greenhouse starts ornamental plants from seeds or cuttings. Transplant eligible plants to the flower or vegetable garden according to your zoning and season of the year.

Plants require warmth, moisture, and humidity to live in a greenhouse. They will still call for adequate spacing; do not crowd. A tall ornamental plant, such as palm trees, will outgrow the height of the greenhouse and puncture the roof.

Decide to specialize in raising one type of vegetation or a variety. Cultivating a variety of plants requires research for companionability. Certain fruits and vegetables cannot thrive side by side. Specialty plants call for special care. Starting plants indoors to remove to outside gardens require containers and meeting planting seasons.

A small cold frame in a backyard.

A small cold frame in a backyard.

Cold Frame Box

The cold frame is a small wood container with a protective glass or plastic cover. This container provides seedlings shelter from wind, other harsh weather and provides warmth. This container helps young plants acclimate through the middle stage of growth. When plants gain their strength and can weather the elements, we plant them into the garden.

Three stages of transplanting:

  1. Use seed-starting trays in a greenhouse.
  2. Transfer seedlings to a cold frame for continued growth.
  3. Move larger plants to flower or vegetable gardens for direct contact with nature.

Moving these plants in their three stages of growth will eliminate shock and promote growth.

How to Use a Greenhouse and Supplies You'll Need