A small greenhouse, typically defined as a compact structure under 100 square feet, presents a unique challenge for gardeners. While it provides a controlled microclimate, offering protection from frost and extending the growing season, its size limits the volume of plants that can be grown. Successfully cultivating a diverse harvest in this limited space requires a strategic approach that prioritizes efficiency. This involves careful selection of plant varieties and the complete utilization of the greenhouse’s three-dimensional volume.
Strategies for Maximizing Space
The key to a productive small greenhouse is thinking vertically, transforming the limited floor area into a multi-tiered growing environment. Installing tiered shelving or stackable racks instantly multiplies the available surface area, allowing for the cultivation of seed trays, microgreens, and herbs. Placing heavier pots or plants requiring less intense light on the lower tiers is an effective organizational tactic. The brighter, higher shelves should be reserved for sun-loving seedlings.
Containers should be chosen carefully to balance root health with space conservation, as oversized pots waste valuable real estate. Using hanging baskets suspended from the roof structure takes advantage of the upper space, perfect for trailing plants or compact herbs. Incorporating wall-mounted trellising systems transforms horizontal growth into vertical production. This supports vining crops like cucumbers and tomatoes.
A cohesive layout involves minimizing pathways and maximizing bench space to ensure easy access without sacrificing growing area. Consider fold-down benches or modular systems that can be moved or adjusted as plants mature. Strategically grouping plants with similar light and watering requirements simplifies maintenance. For example, placing drought-tolerant herbs in one section prevents accidental over or under-watering of neighboring crops.
Compact and Quick-Harvest Crops
Focusing on crops with a short time to maturity and a high turnover rate ensures a continuous yield from the limited greenhouse space. Leafy greens are an ideal choice, as varieties like cut-and-come-again lettuce, spinach, and baby kale can be harvested repeatedly. This maintains consistent production. These crops thrive in shallow containers or tiered systems, optimizing the use of bench space.
Microgreens, which are seedlings harvested shortly after the first true leaves appear, are the most efficient crop for a small structure. Their entire lifecycle is often completed within seven to fourteen days, allowing for continuous succession planting and the highest yield per square foot. Culinary herbs, such as basil, chives, and mint, also offer continuous harvesting. They can be easily managed in small pots or hanging planters, fitting into tight corners.
Root vegetables are excellent candidates for container growing within the greenhouse, provided the containers are deep enough to accommodate root development. Quick-maturing crops like radishes and Hakurei turnips can be ready for harvest in under a month and can be sown densely. Carrots, particularly Nantes or Chantenay varieties, are also well-suited for deep containers. They can be thinned progressively, with the thinnings used as baby carrots to maximize resource utilization.
Heat-Loving and Long-Season Plants
Many small greenhouse owners purchase the structure specifically to cultivate heat-intensive, long-season crops that struggle to mature in cooler climates. Vining plants such as tomatoes and cucumbers are popular choices, but they require vertical management to prevent them from overwhelming the space. Indeterminate tomato varieties need regular pruning to remove suckers and training on high-wire trellises. This encourages upward growth and focuses the plant’s energy on fruit production.
Cucumbers, especially smaller pickling or snacking varieties, are heavy producers that must also be trellised to maximize yield. Using supports like netting or string allows these plants to climb the full height of the greenhouse, utilizing the entire cubic volume. Peppers and eggplant thrive in the controlled warmth of a greenhouse. They often produce higher and longer yields than they would outdoors.
For peppers, a temperature range of 70–85°F during the day is ideal for fruit set, making the greenhouse environment particularly beneficial. Pruning the lower leaves of pepper and tomato plants helps improve air circulation near the soil. This reduces the risk of soil-borne diseases in the warm, humid greenhouse air. High-value, exotic crops like ginger or dwarf citrus trees can also be grown if the structure maintains a consistent warm temperature.