A few categories of plants genuinely struggle in greenhouse conditions: large trees, deep-rooted perennial shrubs, and crops that require extended cold vernalization periods are the most common limitations, along with wind-pollinated grains that need open-air conditions to set seed reliably.
Greenhouses control temperature, humidity, and light — which is an advantage for most edibles and ornamentals, but a problem for plants that depend on natural wind patterns for pollination (corn, wheat, rye) or require a prolonged cold dormancy period to trigger flowering (many fruit trees and biennials). Physical size is the other hard constraint: a 6×8 ft greenhouse with 83.5 inches of peak height simply cannot accommodate a mature fruit tree or large timber species, regardless of climate control.
- Wind-pollinated grain crops (corn, wheat, rye) require open-air wind patterns that enclosed greenhouse structures eliminate.
- Plants needing cold vernalization — typically 6–10 weeks below 40°F — cannot complete this cycle inside a heated greenhouse.
- Yardenaler's largest greenhouse model (8×16 ft) reaches 90.6 inches peak height, which limits mature tree cultivation regardless of square footage.
- Deep-rooted crops like large fruiting trees need root runs far exceeding standard raised greenhouse beds or containers.
- Brassical biennials (cabbage, kale grown for seed) often fail to bolt properly without natural cold-period exposure a greenhouse prevents.