Authored by: James W. Brown
You've decided to take the plunge and purchase a hobby greenhouse. Once you’ve received and constructed it, it’s time to get it ready for plants and for making decisions on what you want to grow. It is likely that your list of plants to be grown and things to be done in the greenhouse can be unrealistically long. The information here is intended to help you take a realistic approach. There are many variables in what is realistic. These include the background and experience of the individual grower, the available time they have and what they expect from the project. The following guidelines and suggestions may help the new grower set realistic goals and expectations, which are more likely to result in a satisfying growing experience.
What is to Be Grown?
Once you have your greenhouse ready to provide the needed environment for the plants, the tendency is to overstock the greenhouse. This leads to tough discard decisions when the realization strikes that the greenhouse cannot hold every plant that has been produced. Young plants take up less room than they will need when they get older. If the greenhouse is filled with young plants, it will not be big enough for the plants when they get just a few weeks older.
Determine or find out the space needs of the plants when they reach the growth stage you expect to grow them to in the greenhouse. Calculate the greenhouse space you intend to allocate to that type of plant. Then determine how many of those specific plants you can grow in that space. You may find that you have some decisions to make at this point. Adjusting expectations, however, is usually less painful than disposing of plants that can no longer be accommodated by the available space in the greenhouse.
Overcrowding plants can lead to situations far worse than simple frustration as growers decide what to cull from the collection of plants. Plants will not grow and produce properly when they lack adequate space. They will compete for space and light, thus stretching and not concentrating their energy on flowering and fruiting. Plants stressed in this way are usually more susceptible to diseases and insect damage because crowded foliage provides an environment that protects them in their early development. Therefore, when you make the list of plants to grow in your hobby greenhouse, be realistic, do your homework on the space needs of each plant, and remember it is best to be conservative and add plants later on rather than eliminating plants in an overcrowded greenhouse.
Starting with seeds in the greenhouse is preferable to using cuttings or seedlings from another location. You are much less likely to introduce insect, mite or disease problems to your greenhouse if you start from seeds.
Seed 20 to 30 percent more seeds than the number of plants you want. Not all seeds will germinate all the time and not all the seeds that germinate will produce a strong, vigorous plant. This will mean that you will need to throw away some of the seedlings at transplant time. This is understandably tough for some beginning greenhouse growers. It is, however, the best way to establish a good, healthy plant population in your greenhouse.
What Plants Do You Seed?
The beginning grower needs to make decisions on the kind of plants they want to grow and the number of each of those different plants. Will they be ornamental or edible plants? It’s best to limit the diversity of plants at the beginning. As experience is gained and success is achieved, additional species can be added.
Unfortunately, most new hobby greenhouse growers don’t want to slow down and start at the beginning. They want to immediately achieve their wildest dreams. But those dreams can be best achieved through a series of progressive, successful steps. With a more conservative approach, rewards are much higher and disappointments are few.
Growers who have experience growing plants in the garden or in pots in the south-facing window are in a better position to start with a more demanding type of plant in your greenhouse. Even if you are experienced, moderation the first time around will yield the best results.
Beginning greenhouse growers should consider vegetative plants like lettuce, basil or coleus, which are easy to grow. Bushes and trees should be avoided by beginners. They each take up a lot of space and take a long time to grow. Quicker production and satisfaction can be obtained from faster growing plants.
Tomato, seedless cucumber, eggplant and hot pepper plants are good for the grower with more experience. Bell peppers, which are a little more difficult to manage to good growth, should be left until some experience has been gained with the other fruiting plants such as tomatoes, cucumbers, eggplant and hot peppers.
There are many potential production systems that could be used in the hobby greenhouse. It is not possible to review each one of them individually in this brief article. Once you have decided what plants you want to grow now, and even in the future, you will be in a better position to choose the growing system or systems to obtain for your greenhouse.
Some systems are designed for growing a few plants in a small area. Only small plants should be grown in these systems. Instructions that come with the system may state that you can grow larger plants. Although the larger plants will grow in those systems, they typically will not perform as expected and will produce less than in a system designed for larger plants.
For larger plants like tomatoes and seedless cucumbers, a system that places the plants on or near the floor rather than up on a bench is best. These plants will require a plant support system to keep the stems trained vertically. The plant systems will need to provide adequate plant spacing for the plants to grow and produce adequately.
Limiting yourself to two or three systems will be best for most small hobby greenhouses. The different systems will accommodate different sized plants, allowing for a variety in the greenhouse. By starting with a few growing systems, the hobby grower will not be spread too thin by having to check over a dozen small systems. After all, the entire objective is to grow well and enjoy the experience!
A commercially available general hobby fertilizer will do the job for the beginning grower. Although a commercial greenhouse grower will often use customized recipes based on the plant grown and the water being used, satisfactory results can usually be obtained on the hobby level with commercially available hobby fertilizers.
Hydroponic growers will need a fertilizer designed for hydroponic production. The makers of many fertilizers for soil or other media assume that the media will be contributing some of the fertilizer ingredients required for plant growth. In hydroponic systems, however, all nutrients needed for growth must be supplied in the fertilizer. Commercially available hobby fertilizers will usually have a full array of needed nutrients. Flowering plants have increased requirements of certain nutrients compared to vegetative plants. Some fertilizers have different components in separate containers that are mixed in different ratios for different kinds of plants and for different growth stages.
Growing organically is a little more restrictive but still quite possible to accomplish in the hobby greenhouse, however, it will require a higher level of dedication and time. If the grower is personally using the produce from the greenhouse (i.e. not selling any of it), organic certification is not required. Of course, even if you’re consuming your own produce, you may wish to pursue certification as a personal goal.
Generally, an organic media is going to be a little more complex than the media in the hydroponic system. The media provides some of the nutrition and the basic energy sources and environment for the microbial activity that is an important part of an organic media. Some of the additives used will be for the direct benefit of the microbial activity in the media.
The first and best pest management strategy is to keep pests out of the greenhouse from the beginning. Starting from seed rather than importing started plants or cuttings is one preventative measure that was discussed earlier in this article. Installing insect screening on air intakes will reduce the likelihood of insects and mites getting into the greenhouse.
Outside plants and bushes should be kept away from the greenhouse, since they can harbor unwanted pests. If the grower has an outside garden, the greenhouse work should always be done before going into the garden rather than after. Going into the greenhouse after working in the garden can result in insects or diseases being transported in.
Pets that romp around through the weeds, the garden and the neighbor’s yard should not be allowed into the greenhouse. They can introduce unwanted agents to the greenhouse.
Keep a Step Ahead of Your Plants
In this step-by-step approach to your first hobby greenhouse, one of the most important principles is to keep at least one step ahead of the plants. When plants get ahead of the grower, the grower is no longer in control and a stressful situation (for plant and human alike!) has been allowed to develop. Observing the above suggestions will ensure that the grower remains in control and has a satisfying experience in his first greenhouse.
Growers may consider joining a local garden club where the members have similar interests. A new grower should research the clubs and attend meetings to check them out. Some clubs tend to be highly competitive and made up of long time members who have forgotten what it was like to get started; however, most have many members at varying levels of expertise who can be very helpful and supportive of your efforts.
In closing, being methodical, researching and learning along the way, starting out slowly and gaining knowledge through hands-on experience will make the beginner hobby grower’s path rewarding and fruitful.