“Is it too soon to be putting my plants outside? When can I put them outside?”
Yes, it is a little early for most plants. They have been growing in a greenhouse, so all the new growth that we are thrilled to see is greenhouse growth. When it is warm enough for you to just wear a t-shirt (so perhaps warmer than 13C), then they can go outside, but come back in when it is colder.It may be annoying, but it is a sure way to protect the wonderful growth the plants have made in the greenhouse all these months.
Some plants may tolerate this early cold better than others. Our pansies and perennials were grown in a cold house, with just a little growth since they came into the retail house, so they would be fine outside. Just watch the weather; if it gets below freezing be kind to the new growth and either bring them inside or cover them with a cloth (not plastic) to trap the warm coming from the ground. Our shrubs have only greenhouse growth, so will be just as fragile as our annuals. Hardening off will be needed.
Cold injury is much like we see on the lettuce that shoved to the back of the frig. Damaged tissues on landscape plants may be cosmetic. If the plant is still alive, just the leaves or blooms are damaged. A quick trim and they can face the coming summer.
So be kind to any annual plants you purchase at CP. Play the in-out game until temperatures are consistently 13+C.
Yours in foliage,