How to Harden Off Your Seedlings

How to Harden Off Your Seedlings


Growing plants from seeds is easy, as long as you take a few precautions. One of those precautions is to make sure that you harden off your plants before setting them out in your yard and garden.

Why you should harden seedlings

When plants are grown from seed indoors, the frequently are grown in a controlled environment. The temperature is pretty much maintained, the light is not as strong as full sunlight outside and there will not be much environmental disturbances like wind and rain.

Because a plant that has been grown indoors has never been exposed to the harsher outdoor environment, they do not have any defenses built up to help them deal with them. It is much like a person who has spent all winter indoors will burn very easy in summer sunlight if they have not built up a resistance to the sun.

The way to help your seedlings build up a resistance is to harden off your seedlings. Hardening is an easy process and will make your plants grow better and stronger when you do plant them out into the garden.

Steps for Hardening off Seedlings

Hardening off is really just gradually introducing your baby plants to the great outdoors. Once your seedlings are big enough to plant out and the temperatures are appropriate for planting outside, pack your seedling in an open top box. The box is not absolutely necessary, but you will be moving the plants around quite a bit in the next several days and the box will make transporting the pants easier.

Place the box (with your plants inside) outside in a sheltered, preferable shaded, area. Leave the box there for a few hours and then bring the box back indoors before the evening. Repeat this process over the next few days, leaving the box in its sheltered, shaded spot for a little longer each day.

Once the box is staying outside for the entire day, start the process of moving the box to a sunny area. Repeat the same process. For a few hours each day, move the box from the shaded area to the sunny area increasing the length of time each day until the box is in the sun all day.

During this process, it is best to bring the box in every night. Once the plants are spending the whole day outside, then you will be able to leave them out at night. At this time, it will also be safe for you to plant the seedlings out in your garden.

This whole process should take just a little longer than one week. Taking this one week to help your plants get use to the outdoors will help insure that your plants will have a much easier time growing outside.

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  1. If I grow my plants from seedlings when do I start my seedlings on your A,B,C nutrient mix. When do I start feeding my plants? What amount of mix do I use?

    1. When a seed sprouts, the first set of leaves that unfold are called cotyledons. All the food that's needed to sustain these first leaves is contained right inside the seed. But once the second set of "true" leaves appear, you should begin feeding your seedlings with a diluted solution. Mix the nutrient at half the recommended rate. You can continue this feeding program until the seedlings go into the garden.


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