Has this ever happened to you?:
You found some really nice plants at a nursery, and you knew it was still too cold for them to be planted outside, but you were afraid that if you didn’t get them right then there wouldn’t be any more as nice later, and you figured you could just keep them safe in the garage until it was warm enough.
Or: You bought beautiful plants with the best intentions of planting them right away, but it took longer than you figured, and this and that came up and they ended up spending two weeks in the garage before you finished planting them all.
And while you were planting, in either case, you noticed how the plants didn’t look quite as fresh and bright anymore, but they still seemed OK. And then you waited for them to bloom. You waited. Waited some more. Three weeks, a month, and maybe finally a flower appeared, and then your plants started to seem normal and bloomed like they were supposed to.
What happened? It’s the dreaded Garage Blight. You won’t find this disease listed in any how-to gardening book, or Extension Service publication, not under that name or any other, yet it’s a common springtime malady. There’s no actual disease, as in an illness caused by a virus, fungus or bacteria, of course. It’s simply plants’ response to a bad environment. It kills all flower buds, right down to teeny-tiny ones that you wouldn’t have seen as flowers for another month or more. All it takes is two or three days in a garage or storage shed to bring on the effect, but the longer a plant stays garaged, the more damage is done. They grow out of it if you took good care of them during their confinement, but there will always be that long wait for flowers.
I sometimes claim (exaggeratedly, I admit) that garages are specifically designed not for holding cars, but for destroying plants. A number of factors interact to cause Garage Blight; foremost among them is still, unmoving air. Lack of day/night temperature variations, and low light levels are also problems. The same things are true of storage sheds, if they’re the culprits. Cold concrete floors could be a problem, and fumes from gas and oil might be a factor in some garages, too. But mostly I think it’s those air and temperature problems, which are the result of being in an enclosed space. Your plants want to be free! To breathe the fresh air!
Is there any way around the Garage Blight problem? Yes, don’t put plants in the garage. Leave them on the porch, under cover, but exposed to open air. Even in freezing weather this is generally adequate protection. If your plants will cover more area than one porch provides, use both porches, and any clear area against the house, under the eaves. After all it’s temporary, just don’t trip over them. If you have a new, big, clumsy puppy who will trample anything in his path you may have to think of something else. Ideally, we should all wait until it’s really safe to plant before buying, but I know what impulse purchases are. Also, we should take home only as many plants at a time as we can expect to get planted right away, and we should have our beds all prepared for the new plants, so there’s nothing to delay planting. Again, that impulse factor. I do understand from personal experience, but we must all strive to improve our habits. Our plants will appreciate it.