Usually I start hardening off my tomato starts in mid-May, but when a good weather day comes along in April, as it will today per the weather stations last night on tv, I will begin my tomato exercise program where I pull some trays from the greenhouse and put them outdoors to get some natural sunlight during the day.

Today’s weather in CT (4/28/21) is predicted to be mostly sunny, in the mid-70’s by mid-afternoon, and sunny for the first part of the day, followed by clouds in the afternoon.

per my iPhone app

Location

Years before, I had a slope to deal with and placed them on the ground, now I have a small deck floor area which makes everything level. This helps tremendously. I will put them on portable tables, bins turned over, the wood floor, and on shelves I may have picked up here and there at tag sales or as road side finds. I also have a small drafting table outside which is usually in the greenhouse. It makes a perfect potting station for me. When not being used for potting things up, I put trays on that too.

Weather

Big factor! If it is too windy and cool, I won’t put them out. I also use my weather app on my iPhone. I find this is the most reliable source of hour to hour weather predictions. I also bring a patio umbrella to the area so it is not direct sun for the delicate tomato leaves. And make sure that umbrella is stable. The last thing you want is for it to fall over from wind on your delicate plants! There is a big tree near this staging area, but remember, the trees are not leafed out yet so why I get the umbrella setup as well.

Timing

It is about 47 degrees F outside right now as I write this and cool, with rain from last night. I’m not going to put them out this morning, I’m waiting till it warms up a bit. I’m just particular that way – my tomato plants are my babies! So time of day is just as important as the location and predicted weather for the day.

Care

How your seedlings are cared for is super important this time of year. Spending months prior, seeding the seeds, monitoring the growth, carefully watering the seedlings, and inspecting all along the way. The last thing you want to worry about is damaging them during the hardening phases outdoors. So, I am sure to select the bigger of the seedling plants to go outside and I limit it to only a couple times a day. This makes for a great exercise program, going in and out of the greenhouse, bending and lifting trays, reorganizing only to move it all back inside a few hours later.

Hardening Off Weeks

Usually the best time to start hardening off seedlings is a week or two before when you plan to transplant them into your container gardens, grow bags, patio pots, or gardens. This will acclimate the tender plants gradually for a couple hours every day. However, as noted above, this year, I’m doing some of this early on good days only and carefully monitoring them. I won’t do this on a day that I am not here to watch over them (literally, LOL). It is very important to make sure the place where you do this process outdoors is protected, to do this on non-windy days, and away from any potential problems.

Watering

Another important factor is to make sure you are watering appropriately, monitoring what is drying out, and pay attention to watering needs while hardening off plants. Watering is a tricky thing. You get a sense of how to balance the dry cycles (where the soil gets the oxygen it needs for the roots) and moisture cycles. Watering plants is best in the mornings, but you also don’t want to over water them. After a while, you get a sense of what is working and how the plants respond. It is definitely a science and an art. It also can be intuitive if you have a green thumb or are obsessed with plants, or it is an exact science. In fact, some big growers actually weigh the plants at different parts of the day and do this all by exact numbers and creating graphs! As for myself, I sometimes will observe if the soil looks dry on the top, feel the tray or pots for their moisture weight, know when I last watered, and in some cases, may take a seedling out to look at the roots and moisture. You want the moisture to be lower so the roots grow downward (versus wet on the top of the soil profile, which would not encourage downward root growth).

Plant Size

Some of my plants are in 5″ squares and others are still in 3″ round pots. I typically select only the larger seedlings for hardening off a bit early. The more delicate small ones I would not risk doing this early. It also helps to give the plants some natural air circulation by placing them outside in a protected location. I’m actually still potting up seedlings, even some which are still in the seedling starter trays. So, there are several different sizes and stages to my seedlings.

I feel especially impatient this year because it felt like a long winter. I can’t wait to put all my plants outdoors permanently but we must hold back. If you try to cross the finish line too early, you risk all the hard work you put into starting the plants from seed in the first place. But hopefully all goes according to plan with no problems so you can look forward to eating big yummy juicy fresh tomatoes, like this one shown below from last year!

Thank you for visiting. Please feel free to ask questions.

Cathy Testa
860-977-9473
containercathy@gmail.com
Container Garden Designer
Small Time Grower
One-Woman Owned Business
Plant Enthusiast
Location: Broad Brook, Connecticut
Post dated: April 28, 2021