Editor’s Note: Changes made on November 15, 2017
If you have a green thumb, it doesn’t matter what climate or geographical location you’re in – you’ve looked into building your own greenhouse facility to provide year-round growth and crop production for your family. But ask any experienced gardener or horticulturist and they’ll tell you the same thing: not all greenhouses are made equal. Many first-time greenhouse owners make the simple mistake of rushing toward their nearest big-box home improvement store without doing sufficient research. Depending on your climate, budget, intended usage, and commitment to a robust and functional greenhouse facility, you’ll need to do some extra legwork before you make a decision on a brand-name greenhouse or a DIY structure.
A Brief History of Greenhouses
The earliest known example of food production in a greenhouse-like structure was under the rule of Roman Emperor Tiberius during the 1st century A.D. An ailing Tiberius, instructed by his physicians to eat a daily staple of cucumbers, was perplexed as to why the technologically superior Roman Empire was unable to provide him with a year-round supply of the vegetable.
A specularium was constructed in the capital using stone and thin sheets of mica. Fires outside the stone walls were constantly maintained in order to heat the air inside and a semi-transparent roof was built from the mica to allow sunlight to enter indoors.
Horticulture laid largely dormant for the next 1500 years until the 16th century when Italian scientists were faced with housing and studying exotic, fragile plants brought back by overseas explorers. The concepts and designs spread to the Netherlands, France, and England with varying results. It was only when French botanist Jules Charles built his own greenhouse that the era of modern greenhouses began and a foundation for the rest of the horticulture world was established. 
Today, modern greenhouses are built with cutting-edge fabric and steel designs to provide lightweight, energy-efficient performance in a dizzying variety of shapes and sizes. Furthermore, modern greenhouses can be equipped with precise temperature and humidity control units, LED lighting and plug-and-play electrical systems, and custom translucent patterns to maximize available sunlight depending on the user’s region and longitude.
The Benefits of Growing Plants in a Greenhouse
- Consistency and reliability in quality of produce grown.
- Extended growing season.
- Expanded variety of available crops.
- Protection against animal and insect infestation.
- Higher nutrient count in carefully-grown produce.
- Easy-to-control growth environment, soil, and humidity levels. 
The first step in becoming a greenhouse owner is to decide where you’ll place your structure and how much space you’re willing to dedicate to it. Before you decide whether to build or buy a greenhouse, consider the following:  
- How many different types of plants do I want to grow in my greenhouse? How much space will the plants require?
- Are there any deciduous trees nearby that can provide shade in the summer and sunlight in the winter?
- If I place my greenhouse too far from my home, will I be able to take advantage of our existing water and electrical connections?
- Is the soil suitable for drainage or should I implement a water recycling system?
- What material will I use for the foundation?
- Does my area’s climate require special climate control systems or strategies?
Because greenhouses require at least 6 hours of direct sunlight per day (particularly during the winter), its imperative to orient and place your greenhouse properly to provide maximum exposure to sunlight. In the Northern Hemisphere, orienting your greenhouse from east to west with the largest side facing south with get the most exposure to natural light, but you’ll still want to augment your greenhouse with energy-efficient grow lights. 
Ultimately, choosing between an all-in-one greenhouse solution and a structure of your own design depends on your commitment to the project and how interested you are in the nitty-gritty details of your greenhouse system. The more custom and personalized your requirements, the better off you’ll be with a DIY project (if you have the skills and tools necessary to make it a reality). However, if you’re interested in establishing a side business or perhaps becoming a first-time legal cannabis producer, investing in a reliable, high-performance greenhouse from a trusted manufacturer may be the better option.
How to Prepare for Your First Growing Season
Beginning your journey with indoor plant production depends on what plants you’d like to focus on, but as a general rule, first-time greenhouse producers should get their feet wet (perhaps literally) with a few easy, straight forward crops before tackling something more delicate like strawberries or pineapples.
Tomatoes, leafy greens like spinach or lettuce, and root vegetables like carrots and turnips are good places to start. By grouping together plants with similar growth cycles will help you schedule your production and organize your greenhouse going forward. 
How Many Seeds Should I Plant?
Expect to plant between 20-30 percent more seeds than you expect to grow.  Not all seeds will germinate, nor will each successful seed produce a robust, healthy plant. This will help save you time and energy once the seedlings appear in the soil and need to be transplanted.
If you’re planning to grow plants that require a vertical stem system such as tomatoes, cucumbers, or beans, planting them on a bench or slightly raised platform on the floor will help encourage verticality and provide adequate spacing as they begin to grow.
As far as fertilizers go, many greenhouse owners prefer the organic route, but the difficulties with organic seeds may bring frustrating results during your first attempt. Finding natural fertilizers or composted soil is a good alternative, but if you’re focused on hydroponic growth, you’ll need to augment your plants with a hobby fertilizer to provide the needed nutrients.
Most experienced greenhouse growers recommend against the use of pesticides for indoor growth. A proper greenhouse will protect against outside contamination by pests and diseases, but there are a few steps growers can take to further minimize that risk. 
Installing insect screens on air intakes and exhausts can prevent insects and mites from entering the greenhouse, but the common variable in most greenhouses is the grower themselves. Be sure to establish different standards and equipment (included gloves and tools) between any outdoor gardens you may have and those of your greenhouse. Cross contamination by foreign materials can introduce insects and diseases into your greenhouse’s comparatively delicate ecosystem.
Planting in Warm Weather vs. Cold Weather
Despite the perks of indoor greenhouse growth, it can be very costly to produce warm-weather crops during cold periods of the year (and visa versa). The energy costs alone are enough to turn most greenhouse growers away from off-season production, so it’s wise to maintain a plant’s natural growth cycle and respect nature’s design. 
Fortunately, both warm and cold-weather crops can be a fun and delicious project for greenhouse growers. During the colder months of December or January, plant heartier vegetables such as beets, leafy greens, chard, spinach, onions, turnips, radishes, and carrots. Beets, carrots, and onions can be transplanted almost year-round, leaving plenty of opportunity for continued growth well through the spring and summer. 
When things begin to warm up in March and April, begin planting your more delicate crops. Broccoli, lettuce, cauliflower, tomatoes, beans, cucumbers, squash, peppers, peas, corn, and melons are all ideally grown at temperatures between 55 and 70 degrees Fahrenheit. You’ll also be able to follow this planting schedule for annual flowers that may not survive outdoors.
Despite the considerable amount of time, effort, and research, the benefits of growing your own food in a protected greenhouse should be very clear. Self-sufficiency, high-quality produce, and reliable growth year-round are just the beginning – as you learn and grow along with your crops, you’ll be able to expand on your expertise and begin growing more delicate and rare plants to impress your friends, family, and even potential customers for years to come.