Asked by: Toma Fairclough
home and garden landscaping

How can I harden my tomato plants?

Last Updated: 22nd June, 2020

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.
  2. Raise exposure.
  3. Monitor seedlings.
  4. Finally, leave tomatoes out overnight.

Click to see full answer.

People also ask, how do you harden off plants?

Here's what to do:

  1. Check your seedlings' frost dates.
  2. Stop indoor watering or fertilizing.
  3. Choose your first hardening off spot.
  4. Place your seedlings outside for an hour.
  5. Move your plants back indoors.
  6. Lengthen the hardening off time.
  7. Protect your seedlings as needed.
  8. Extend nighttime hardening off hours.

Furthermore, do you need to harden off plants? Hardening off should take a minimum of a week and may take up to two. Suddenly moving plants from a stable environment to one with wide variations in temperature, light and wind can seriously weaken plants. For most plants, start hardening off about a week before the final frost date for your area.

In respect to this, 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.

When should you cover tomatoes at night?

Use a Cover to Protect Tomatoes When frost or temperatures are in the forecast for overnight (mid-30s or even 40ºF), cover your tomato plants with clear plastic or a tarp.

Related Question Answers

Xiana Gfrorer


How tall should my tomato plants be?

Indeterminate tomatoes will grow and produce fruit until killed by frost. They can reach heights of up to 12 feet although 6 feet is normal. Indeterminates will bloom, set new fruit and ripen fruit all at the same time throughout the season. They require substantial staking for support.

Jesusa Pache


How tall should tomato plants be before planting outside?

To be sure their seedlings have a good root system, many gardeners prefer to repot them a second time before setting them out in the garden. Wait until seedlings are six to 10 inches tall. A good rule is to transplant when the height of your seedling is three times the diameter of its pot.

Alvaro Kroich


When should I start hardening my plants?

For most plants, begin hardening off a week before the final frost date for your area. Our Garden Planner uses data from your closest weather station to recommend when it's safe to plant out, providing a helpful guide to work back from. Choose a sheltered spot to harden off your plants.

Savu Rudraraju


Should tomatoes be fertilized?

Tomatoes should be first fertilized when you plant them in the garden. You can then wait until they set fruit to start fertilizing again. After the tomato plants start growing fruit, add light fertilizer once every one to two weeks until the first frost kills the plant.

Tayeb Cantos


How much space do cherry tomato plants need?

Vining plants (also called indeterminate) can be planted about 1 foot apart in row, while bush types (determinate) will need about 2 feet between them. Bush cherry tomatoes will be sturdy enough to stay upright on their own but indeterminate plants will need some support.

Audrea Warcho


Should you pinch out tomato plants?

Pinch out tips
You can leave greenhouse plants to grow on. I prefer not to cut them off in their prime, but let them develop until early September before pinching out the growing tip of the main shoot a couple of leaves beyond the topmost flowers.

Melitona Crasto


How do you fix leggy plants?

If the soil is warm enough and the seedlings are mature enough to be transplanted, harden them off and get them outside in the sun to keep them from growing leggier. If you have leggy tomato seedlings, the best way to correct them is to repot them (or transplant them) and bury the stems up to the lowest set of leaves.

Nayem Rabanal


Should I fertilize after transplanting?

Fertilization at the time of planting is generally not recommended. It is ineffective until the root system has a chance to reestablish. It is usually advisable to wait two or three years before applying fertilizer, and then it is recommended to get a soil test first.

Eugeny Uttenreuther


What is hardening of plants?

Hardening is the process of exposing transplants (seedlings) gradually to outdoor conditions. It enables your transplants to withstand the changes in environmental conditions they will face when planted outside in the garden. Reduce the frequency of watering to slow plant growth, but don't allow plants to wilt.

Rudesinda Araluze


How do you acclimate plants?

Upon arrival, keep your plants and trees in the pots they arrived in and place them in a sheltered, shady spot outdoors – like on a back porch. Leave them there for 3-4 hours and gradually increase the time spent outside by 1-2 hours per day. Bring the plants back indoors each night.

Eufemiano Esponda


How do you harden pepper and tomato leaves?

Steps for Hardening Off Tomatoes
  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.
  2. Raise exposure.
  3. Monitor seedlings.
  4. Finally, leave tomatoes out overnight.

Festus Pelecha


How do I harden my plants in a cold frame?

To begin hardening off plants, place them into a shaded cold frame on a cloudy day for a few hours. Then, close the frame. Gradually, increase the amount of sunlight the transplants receive and how long the frame remains open each day.

Damian Mareque


What is the best time of day to transplant plants?

Spring is also a good time to transplant perennial plants like daylilies. Best time of day to transplant is early in the morning, late in the afternoon or on a cloudy day. This will allow the plants to settle in out of direct sunlight.

Eloi Jorda


How can damping off be prevented?

Damping off can be reduced by planting fungicide-treated seed directly into the garden. Other preventative measures include using well-drained soil and avoiding overcrowding of plants. Also, clean out all pots thoroughly before reuse and discard contaminated soil.

Aycha Enukidze


Do you need to acclimate plants?

No, plants are not like fish in that regard. For the most part no, however, if they are still cold from being shipped it's a good idea to let them come to room temperature before planting. I never acclimate plants. Just plant it.

Ikerne Aveiro


Can leggy seedlings recover?

Seedlings also grow leggy when they are started too early. Once seedlings get too long and leggy many wonder if they can sink the stems lower in the soil once the plants are put outside. This works for tomato plants but most others can't be sunk into the ground in that way.

Riham Quintano


How long do you need to harden off plants?

Guide to Hardening-off
Harden off gradually, so that seedlings become accustomed to strong sunlight, cool nights and less-frequent watering over a 7-10 day period. On a mild day, start with 2-3 hours of sun in a sheltered location. Protect seedlings from strong sun, wind, hard rain and cool temperatures.

Ocie Bostelman


Yamira Jugai


When can I bring my plants outside?

Put them outside
Most houseplants be put outside between May and September. Timings do vary around the country and from year to year, so to be safe, wait until about 2-4 weeks since the last frost. If your garden is exposed, then you may also choose to wait a little later.