Weather acclimation of plants

Acclimating plants grown inside or in a greenhouse is called hardening off. Hardening off thickens the cuticle of their leaves to avoid access moisture loss and strengthens tender young plants. If you are planting potatoes, onions, asparagus, strawberry bare roots, or anything completely under the soil you do not need to take these steps.

Slowly acclimating plants to the reduced humidity, stronger winds, and lower or higher temps than the greenhouse, will reduce stress to your plant.

How to harden off plants grown inside or in greenhouses:

Hardening off takes 1 to 2 weeks depending on the weather and your available time. One week is usually sufficient. When there is a very windy day, heavy rains or quick rise in temps on clear sunny day avoid direct exposure when you are going through the hardening off process.

*Best to do this when temps are 50F or above. Cold-tolerant plants like pansies and cole crops can handle ~40F temps when starting this process.

Day 1: Start by placing them in a sheltered, shady spot for a few hours, then bring them inside at night.

Day 2: Move them to full sun for 1-2 hours; morning sun is best, then shade, and indoors at night.

Day 3: Increase sun exposure to 3-4 hours, followed by shade, then inside at night.

Day 4: Add 1-2 hours more of sun daily until they get at least 6 hours.

Complete the hardening off in about a week, gradually exposing them to more sunlight, wind, and temperature changes. Check the soil daily; water when the top few inches dry out to ensure oxygen reaches the roots.

Acclimate slower if you see signs of stress. Signs of stress can be quickly can be wilting in the sun, scorched leaves, and/or drooping. Movement from the wind is beneficial but not in excess to cause complete drooping over for long periods.

After you notice they aren’t stressed and looking healthy, you can keep them outside! Spring can have drastic temperature swings so always keep on eye out until threat of frost has passed.

How to harden off perennials grown under sun protection:

During the sunniest and warmest part of the year, perennials growing under shade cloth may benefit from a quick 2-3 day acclimation. When you buy plants grown under shade cloth that have already been exposed to wind and fluctuating temperatures, hardening off is focused on increasing sun exposure for full sun perennials. Shade perennials should go in the ground right away.

It’s a quicker process than annuals and if you choose to plant during consecutive cloudy and cool days, planting in their permanent spot is usually fine!

Reminder to check the soil moisture daily. Water your plants when the top few inches of soil are dry.