How to Harden Off Tomato Plants to Prepare Them For the Home Garden

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Updated 4.28.24

Harden off your tomato plants before you set them out in the home garden. Outdoors can be a shock for them if they’re not ready. It’s up to you to prepare them for the real world.

Until now, your tomato seedlings have had an easy life. You’ve pampered them with plenty of light, water, food, and warmth.

That’s about to change.

Tomato Growing Tip #45: harden off tomato seedlings for 7-10 days before planting and other helpful gardening tips for tomatoes with Tomato Dirt #growingtomatoes

In the outdoor garden, your tomato plants have to stand on their own roots and deal with sun, wind, and critters.

About 7-10 days before planting them outdoors, help acclimate them to temperatures, sunlight, and wind.

This process is called “hardening off.” Without hardening off, your tomatoes are more susceptible to sunburn, windburn, and breakage.

Gradual exposure helps your plants toughen up and reduces the possibility of injury. With proper hardening off, they’ll have an easier transition to the garden and begin producing fruit sooner.

Steps for Hardening Off Tomatoes

Take these steps to harden off your tomato plants.

1. Start slowly. For the first day, set plants outside in the shade, next to the house, or in a protected area for an hour or two. Eastern or northern exposure out of direct sunlight also works. Bring seedlings in at night.

2. Raise exposure. Gradually increase the amount of time your plants are outside each day for several days, to include some direct sunlight. Light breezes help strengthen stems as long as movement isn’t too severe.

3. Monitor seedlings. Check them regularly for wilting and water appropriately if they droop. Move them to shade or a sheltered location if seedlings they appear stressed.

4. Finally, leave tomatoes out overnight. Make sure the forecast is for temperatures to be above 50°F during the night time.

Once your seedlings handle their outdoor sleepovers without problem, it’s time to move them into their new home: your garden.

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