Hardening off is the process in which your tender indoor-grown seedlings become adjusted to the harsher conditions of outdoor life before being planted in the ground. Harsh sunlight, drying winds and fluctuating temperatures can be quite damaging and even lethal to tender plants not prepared for life outside. To ensure the best chances for survival, it’s important to introduce seedlings to their new growing conditions slowly.
One week before setting out, begin to prepare your indoor seedlings by watering and fertilizing less frequently. Seedlings in flats should be divided by cutting through the soil with a sharp knife to separate root growth. (This isn’t necessary when growing in individual cell packs.) Drier conditions indoors will serve to toughen the seedling for its first trip outdoors. After a week inside with less water it’s time to bring your seedlings out into the real world. This is a gradual process and shouldn’t be rushed or even the healthiest seedlings will react by drooping.
The first day, preferably an overcast one, the seedling trays should be brought out into dappled shade in a sheltered area for just a few hours. Over the course of a week, increase the seedlings exposure to the sunlight as well as increasing the length of time they’re outdoors. Be very careful to check the soil and water as necessary, the flats will dry out quickly. Add only enough water to prevent the seedlings from wilting. By the end of the week your seedlings should be ready for transplanting into their permanent beds. Careful observation of your seedlings will guide you as to whether they need another day or two of adjusting first. Plant your seedlings on a slightly overcast day and fertilize and water well after transplanting.
That’s it! It’s isn’t a complicated process, but it’s an important one. By not hurrying through this important last step you’ll be rewarded with well-adjusted plants that will grow and produce all season long. Happy gardening!
Great tutorial, Lisa. Impatient by nature, I sometimes skip this step and am always sorry I did!
Thanks! Unfortunately when I started out long ago I learned this lesson the hard way! A garden is a wonderful place to learn patience…
I’d not heard about the withholding water part before, but it makes sense!
I didn’t follow that bit of hardening off advice for years. It does make a difference! Cutting back on watering the week before planting out “toughens” the seedling leaves before their first trip outdoors.
Very timely article on hardening off – so important for success. I am one of those who learned the hard way many years ago.
Eileen
Thank you Eileen! Yes, unfortunately I also learned the hard way not to rush planting out. Here’s to a wonderful garden year!
I am just starting my first vegetable garden this year and just found your site. I was wondering if this process of hardening off is meant for vegetable seedlings or flowers or both? I think you are talking about vegetable seedlings, but just wanted to be sure. Looking forward to reading your blog:)
Hi and good for you starting your first vegetable garden! It’s a wonderful treat to have fresh food right at your fingertips! To answer your question, hardening off is for both flowers and vegetables started indoors from seed. The growing conditions inside are quite different from the “real world” conditions outdoors and an adjustment period is necessary to maintain plant vigor and health. After spending time sowing seeds and nurturing seedlings don’t rush this last important step before planting. Best of luck and thanks for reading!
Thank you Lisa! Your site is wonderful. I’ve been reading some of the previous posts. So glad I found it!