Taoist's guide to gardening and the quest for the perfect bagel: Hardening off seedlings

In my previous post labeled "Hardening Off Seedlings" dated April 17, 2012 I stated that I had a cold frame that I could store my seedlings for weeks if need be. Here is the picture of it;

The caption that accompanied this picture in that post was "I can keep then here for weeks if need be. I simply raise or lower the lid as needed." And that was true enough. What I didn't realize and what took a difficult learning experience to teach me was; just like with my frost blankets, frost and freeze if severe enough will damage plants if the plants are touching the underside of their protection. So in other words, for hard frost and freeze protection plants need to have an air buffer between them and the underside of whatever if protecting them from the cold, whether it's a frost blanket that needs to be held up above the plants to allow for the air buffer, or the lid of my cold frame, that needs to allow for an air space between the underside of the lid and the plants. As you can see in this picture especially if you enlarge it, the tomato and pepper plants in the middle back and right back respectively are darn near high enough to be up against the underside of the lid when the lid is closed.

A week after the picture above was taken we got a hard freeze. The tomato pepper plants were taller by then and were definitely up against the underside of the cold frame when I closed the lid that night. The outcome was not pretty;


All my hard work down the drain. Those tomato plants now all brown were 8 weeks old. The pepper plants to the right were 10 weeks old, the cucumbers in the front right were only 2 weeks old, and the melons in the front middle were about 3 weeks old

I believe that the tomatoes and peppers got hit because they were touching the underside of the lid, which is just 4 mil plastic, but who knows. The cold frame is not air tight, there a gaps between the boards, and considering that the cucumbers and melons got hit as well and they were no where near the underside of the lid indicates that the cold simply got into the cold frame in general. However it did, the result sucked.

I lost almost all the cucumbers, most of the melons. The tomatoes all turned brown yet the thick stem of each tomato plant continued to look like it was alive, the peppers all lost the top most leaves yet still looked like they would survive.

So the lesson to be learned is this;

My pole barn is near my garden, near my cold frame. The barn has electricity, so I figured out how to run a long extension cord from the barn into the cold frame. In the cold frame I attached a series of three work lights to the extension cord, each one plugged into the other, each one equipped with a 100 watt incandescent light bulb. Now granted the threat of a hard freeze is over for the year, and the lesson I learned was costly as far as I am concerned. Allot of effort on my part to grow those now dead plants went down the drain. But I do believe that I know what to do next year to keep this from happening again. The three 100 watt lights will give off just enough heat to keep the inside of the cold frame from getting to the freezing point.

I ended up replanting the cucumbers and melons in my grow room, they are now only two weeks behind schedule, that is no big deal.

The peppers lived and were actually planted this weekend. Here is what they look like two weeks after nearly getting killed by frost;

I am lucky I did not lose my peppers. I would have been hard pressed to replace my peppers, I have ones that you can't by at the local nursery.

After the first rain we got last night

The tomato species that I had planted this year on the other hand are available at local nurseries. So as much as it goes against my grain, instead of starting over with seed, and being 8 weeks behind schedule, I opted to purchase tomato plants. I got the same kinds that I had lost, it's just that I did not grow them.

I have pictures of them, but first it is interesting to note that the tomato plants that got hit by the freeze are trying to make a come back. Look closely at the expanded versions of the pictures below and you will notice the new growth. So given time I think that these would have come back and survived, yet I was not willing to wait.

Note the new growth

This is two weeks after the freeze. So they did not die, and they might still produce viable tomato plants. I am not willing to wait to find out

Here are the purchased tomato plants, they also went in this weekend;

This is what my plants should have looked like. It just kills me to use purchased plants

And so the 2012 season progresses. So far as usual my learning has come at a high price. Yet that is the way it goes, nothing is free, nothing worth while comes easy.

About a week ago, I started to harden off my seedlings. This is a very important step to growing vegetable seedlings indoors. Hardening off simply means to slowly introduce the seedlings to the outdoor environment.

I can't stress enough how important it is to do this and to do it slowly. If you try to skip this step or do it too quickly you will kill your seedlings.

Your seedlings were germinated and have been growing in an optimum environment. They have been kept well watered, at the perfect temperature and have never known wind, direct sunlight or bugs. You have to introduce them to the real world slowly.

The way I do it, is to start about a week or more before I want to transplant seedlings into the garden. I put the plants on my back porch out of direct sunlight, on a day that has little to no wind, and is about 50° - 60°. I leave them there for no more than two hours and back into the grow room they go.

The second day, I expose them to the same conditions but for about 4 hours this time. It is important at this time not to have any direct sunlight or significant wind.

Third day, now we can slowly introduce direct sunlight, still beware of wind. I try to have this be a Saturday, so I am home and can keep an eye on the seedlings while there out. I try to go for about 6 hours of direct sunlight on the third day,

The forth day, I go for eight hours, direct sunlight, slight wind if I am lucky.

Fifth day, I go for all day, direct sunlight, slight wind, and I expose them to the night air, until about 10pm.

From the sixth day on, I leave them out, preferable in a place that protects them from high wind, round the clock.

After a couple of days of round the clock exposure, I place my seedlings into my cold frame until I am ready to transplant them. I regulate the environment inside the cold frame, by how much I open the lid. I can hold them in the cold frame for weeks.