Whether you grow your own tomato transplants from seed or you purchase ready to go plants from your local nursery or greenhouse, one of the most important things you can do for your young tomato plants is to harden them off before planting.
Hardening off is the process of preparing a plant for life outdoors. And for tomatoes, it can make a huge difference in whether they quickly establish their roots and begin to grow, or whether they struggle to grow at all after planting.
When tomato seedlings first sprout and grow indoors, life is easy. In fact, they have little to worry about. Not only is the temperature indoors warm and constant, thanks to artificial lighting, they can also get the perfect amount of light to grow strong and healthy.
In addition, plants can also receive the ideal amount of water and nutrients. And if all of that didn’t make life easy enough for them, they never have to worry about wind, rain, or spring storms that can easily damage their fragile stems and leaves.
But does all of that ever change the minute a tomato transplant goes in the ground outdoors. And if your tomato plants haven’t been properly prepared for what they are about to face, it can spell disaster for your plants – and your future harvest!
How To Harden Off Tomato Plants Before Planting
Let’s face it, spring weather can be unpredictable and harsh. One day, the sun can be shining bright and warm at 75°(F). And that very same night, the temperature can plummet to 45° with strong winds and rain.
Unfortunately, if a tomato transplant goes straight from growing indoors under perfect conditions to wild swings of temperatures, wind and sun outdoors, it simply can’t handle it. Its thin stems and leaves struggle – and can break off with the slightest of wind.
That same wind can also wind-whip young transplants, often injuring them or even killing them in the process. And if those temperatures plummet too low or soar to high on unprepared plants – it can cause the plants to go into shock, totally stalling any growth.
But all of this can be avoided by simply hardening off your plants before planting. The process toughens plants up slowly, allowing them to get acclimated to the outdoors. And once they do, they can handle almost anything Mother Nature can throw at them.
So when should you start hardening off your tomato plants? And, more importantly, what is the best way to do it? The answer actually depends on whether you grew your own transplants from seed, or purchased from a local store.
To be sure, you need to harden off both before planting to ensure success. But as you will see below, the process for store bought plants can be a bit quicker in most cases.
How To Harden Off Home Grown Tomato Plants
For plants you have been growing indoors, it’s best to start the hardening off process a full two to three weeks prior to planting.
Start by taking your plants outside during the day when the temperature is at least 55°(F). It’s important the first few days to really give your plants protection outside. Place plants on a covered porch or patio, and provide them some sort of protection from the wind.
Listen In Below On How To Harden Off Vegetable & Flower Plants!
For this, you can place a couple of boards around plants, or set them down in a box. The idea is to keep any wind from whipping the plants back and forth. A gentle breeze or rustling of their leaves is actually good for them. But whatever you do, don’t let strong winds toss them about.
The first few days, allow them to get a bit of sunlight, but just a few hours each day. Continue to allow the plants a bit more time out with each passing day, and a bit more time in the sun.
After the first week, as long as the weather remains agreeable, move plants for longer and longer periods in the sun. Adding an hour or two each day is ideal. Again, even as they grow stronger, give them protection against the wind.
As each day passes, their stems and leaves will become stronger and stronger from being outdoors. Finally, about three to four days before planting, if the weather is good, allow your plants to stay out all day. If you can, place them near the exact location where you will plant them.
As long as the temperatures do not drop below 50° at night, keep them out overnight at this point as well. You can rest assured by following this simple process, your home-grown tomatoes will be ready for planting day! See: The Best Way To Plant Tomato Transplants – How To Get Your Tomatoes To Grow Fast!
How To Harden Off Store Bought Tomato Plants
Believe it or not, even store bought plants can benefit from hardening off before planting outdoors. Especially ones that have stayed inside of a large greenhouse or nursery and have not been outdoors.
The good news is that store bought plants are usually more developed than home grown transplants. You can thank automatic watering, controlled heat and fertilizing for that. But, larger plants are less likely to suffer transplant shock, so they will not require as much help.
To harden these plants off, start by giving them three to four hours outside for a few days. Just as with home grown transplants, protect them from the wind. Since the plants are most likely larger, you can allow them more time outdoors each day as long as the weather allows.
Usually, a full week of allowing plants to adjust outdoors is more than enough for nursery or greenhouse transplants. Here is to hardening off your tomato plants this year. And even more, having your plants ready to handle whatever Mother Nature throws at her with ease!
For more on growing tomatoes, check out our article on our sister site This Is My Garden – 4 Must Add Ingredients To Put In Every Tomato Planting Hole!
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