At Heritage Growing Spaces we receive a lot of questions when it comes to successful gardening in a greenhouse.

How do I choose what type of greenhouse to build for successful gardening?

If you want to grow warm-climate plants and experience successful gardening, you’ll need a greenhouse capable of maintaining steady temperatures of 65 to 70 F. Most flowers, vegetables, and herbs need temps of around 55 F. (13 C.), while a “cool” greenhouse is suitable for germinating seeds and raising starter plants in spring. A greenhouse with clear panels provides warmth and light for sprouting seeds. A diffused or glazed covering provides balanced levels of light heat for growing plants to maturity. Additionally, build a greenhouse that is adequately ventilated and insulated to prevent plants from excess heat and cold. For more reading on this topic read our blog post on how to choose the right type of greenhouse.

What plants/vegetables can I grow in a greenhouse?

You can grow nearly any plant you want in a greenhouse. But successful gardening is all about determining the needs of particular plants. For instance, you can germinate seeds and grow starter plants in an unheated greenhouse. However, tropical plants need consistently warm temperatures year-round. You can easily start most flower seeds and cool-season vegetables such as peas, broccoli, and lettuce in an unheated greenhouse. However, tomatoes and peppers need plenty of sunlight and warm temperatures between 55 and 85 F. (12-29 C.).  Some flowers, such as impatiens and ferns, thrive in shade, while geraniums and daisies need bright sunlight. For more helpful information on this topic read our blog post about the ten best plants to grow in a greenhouse.

Can I grow herbs in a greenhouse in winter without a heating system?

In a cool northern climate like Montana, successful gardening will be difficult to grow herbs unless you supplement heat. Most herbs will struggle when temps drop below 40 to 50 F. (4.5-10 C.), while many prefer consistently warm temperatures of 65 to 70 F. (18-21 C.) during the day and 55 to 60 F. (13-16 F.) at night. You can get a jump on spring growing by starting many herb seeds in an unheated greenhouse, but you may need a heat mat for germination. Herbs that tend to be cold and hardy include lavender, garlic, rosemary, winter savory, catnip, and oregano. For more reading on this topic read our blog post about growing vegetables in the winter.

How do I get rid of bugs in a greenhouse?

Surprisingly, even in a greenhouse environment, insect pests are inevitable. These greenhouse pests may range from aphids and mealybugs to mites, whiteflies, and more. One of the easiest ways to monitor them is by using sticky pads. These keep many insects under control or at least signal you when their numbers are growing for further control. The use of insecticidal soap and neem oil are additional methods of control and are normally safe to use on edibles. Read more about how to get rid of pests in your greenhouse.

What is the ideal humidity for starting seedlings in a greenhouse?

Most plants prefer humidity between 50 and 80 percent. Foliage loses water and wilts rapidly when levels are below 50 percent. But high humidity can cause fungal diseases such as damping off, which causes tiny stems to rot at the base. If high humidity is a problem, you can provide a drier environment by watering plants from the bottom, and by providing adequate heat and ventilation. If humidity is too low, improve conditions by misting plants, with cool mist vaporizers or small humidifiers, or by placing pots on trays of wet pebbles.

How do I get rid of mushrooms in greenhouse soil?

Mushrooms often pop up in potting soil, which indicates the substance is high in organic material. Although the fungi are harmless, they tend to be unsightly. If you notice tiny mushrooms, pull them up by their base and discard them to prevent the development of spores. Water plants from the bottom and be careful not to water excessively. Provide proper ventilation to keep the air moving. If air circulation is limited, a small rotating fan will help.

How much does it cost to have a greenhouse built?

Greenhouses have many variables in how they are made. Questions about what you plan to grow, like how many people you would like to feed? Will you be gardening year-round or just in the summer? These are just a few questions that need to be answered before you order a greenhouse. Some of these questions determine the proper materials to be used in building your greenhouse. We recommend starting a relationship by setting up a free consultation to discuss the many variables so that we can determine the right greenhouse for you.