Hardening Off Plants Common Reader Questions and Answers

How do you harden off plants?
What happens if you don't harden off plants?
Will plants die if not hardened off?
Why is hardening off important?
How do you harden a plant before transplanting?
How long do you need to harden off plants?
Will leggy seedlings still grow?
How much water do transplanted plants need?
Do onions need to be hardened off?
Do plants grown in a greenhouse need to be hardened off?
Do pansies need to be hardened off?
Do Annuals need to be hardened off?

How do you harden off plants?

An intermediate home, such as an unheated greenhouse or cold frame, is a great tool for hardening off. Place seedlings and plants into the structure for a couple of hours on the first day, then gradually increase the length of time they are in place by two or more hours per day.

What happens if you don't harden off plants?

If you don't harden your plants, the tender plants will get burned by the sun, the shock of cold, or the wind. ... Some plants may recover from burn (even fully), but their growth will be set back a few weeks while they recover.

Will plants die if not hardened off?

3) Harden Off Your Seedlings: If you don't harden off your indoor seedlings before planting them outside, they will suffer shock from the brutal sun. Without the opportunity to adjust first, they'll get sunburn and might even die.

Why is hardening off important?

Hardening-off is important because it reduces plant stress. It can sometimes take several weeks for newly transplanted plants to really take off and begin growing. ... In the spring, it's common practice to gradually accustom greenhouse vegetable seedlings to full sunlight and drying winds before planting them.

How do you harden a plant before transplanting?

Begin hardening off on a still, cloudy day when temperatures are fairly steady. Water plants before they go outside. Place them into your sheltered spot for just two hours on the first day. The next day, leave them out for two more hours, with perhaps an hour's direct sunshine in the morning.

How long do you need to harden off plants?

In general, the process of hardening off will take about one week, and sometimes up to two weeks if the weather has an unexpected and dramatic drop in temperatures. If your region has frost, you should time your seed starting in spring so the seedlings can start to go outside after the last frost date.

Will leggy seedlings still grow?

Most leggy plants become sturdier once they are growing outside. ... Put a small fan next to your seedlings on a timer so that the plants are blown in the breeze for a couple of hours a day and gently passing your hand over the tops of seedlings a few times every day to stimulate stronger growth.

How much water do transplanted plants need?

On most well drained soil, one inch of water per week throughout summer and fall is required to establish and maintain good growth. In sandy soils, as much as two inches of water per week is needed. Mulch is another important element in good plant health care maintenance.

Do onions need to be hardened off?

Onions are cold hardy and can endure cool spring temperatures. Begin hardening off onion transplants about 4-weeks before your last expected frost date (look up yours here). ... Onions can withstand cool temperatures but the young seedlings are vulnerable to frosts and freezes.

Do plants grown in a greenhouse need to be hardened off?

In northern climates, cool spring temperatures, strong winds and bright sun can be very stressful to plants that have been grown in a greenhouse. To minimize these risks to tender plants a process known as “hardening off” is required.

Do pansies need to be hardened off?

Pansies should be hardened off enough after a week or so outside to be able to handle 20° temperatures without being covered. Deadheading pansies will encourage further blooms. Additionally, if pansies are allowed a period of rest during the hottest months of summer, the re-bloom in fall will be more prominent.

Do Annuals need to be hardened off?

For the best choice of annuals, it is ideal to be at the flower farm and purchase as soon as possible in the spring. However, most years the weather is not yet reliably warm, even by Victoria Day weekend. It's safer to harden off your new annual plants before you put them directly outside.