Petunia Autopsy

I took petunia cuttings Oct. 24 and Nov. 11 and have been caring for them in the garage ever since. There was no indication that they were quickly dying, and some of them put out flowers. But they were not thriving. I took one more cutting Nov. 15, this time using rooting hormone. Over the past month, this one surpassed the others, with greener leaves and a bloom. After a few weeks, roots were visible in the semi-transparent plastic cup, unlike the other cuttings.

Today I decided to take a look at one of the original cuttings to see if it had rooted. No, it had not. There is still some green in the leaves and stem, but this cutting never sent out roots.

That decided the fate of the other seven cuttings that had not been treated with the rooting hormone. They were discarded to make room for a larger pot for the treated cutting. The first image is the roots of the treated cutting. The next image shows the original petunia pot (#1), which has bushed out several inches since it got a haircut a month ago, and the rooted cutting (#2) in its new pot.

This new pot will live in the heated garage for the winter, but I did plant something in the unheated greenhouse today. I ordered a cheap mini-greenhouse (27.5x19x63 inches) to reside inside the big greenhouse to provide an even more sheltered environment for seed starting in the spring. I tested some arugula seeds for viability on Nov. 15, and to my surprise some of them sprouted within three days. I didn't know what to do with them, so today I planted them in a tray and put them on a heat mat inside the mini-greenhouse. I'm interested in seeing how much (if any) the heat mat raises the temperature inside the mini. My concern is that on a sunny winter day, the mini will heat up even more than the greenhouse and fry whatever is inside. The fan has kicked in several times the past week. The greenhouse temperature reached 87 on Dec. 15 when the outside temperature was 61. Yes, December 15th.

I left the watering can inside the mini, theorizing that it may help with humidity and heat retention. The front flap rolls down, sealing the heat and humidity inside and keeping any pests outside. That's the plan anyway. I put the arugula on a low shelf only because the heat mat cord isn't very long.

Update Dec. 20: It got down to 11 degrees outside last night, 21 degrees inside the unheated greenhouse, and 26 in the mini. The arugula is right on the heat mat and the thermometer is a foot above it, so the arugula didn't get frosted. We'll see what happens if it gets really cold. All of the water in the tray disappeared, so with the heat underneath it I'll probably have to fill that every few days. Today as I was emptying dead petunia cups, I looked at the other eight cuttings on which I did not use rooting hormone. None of them rooted. Without hormone: 0-for-9. With hormone: 1-for-1. Small sample size, but I'm convinced. Dec. 22: The plastic cover over the mini was fogged up today, so there is humidity trapped in there. (40 degrees and raining outside.) I added an extension cord and moved the tray to the top shelf, where it will get some light during the day when it is sunny (which today it was not). I brought my infrared thermometer to get a reading off the heat mat, and it was 70-72 degrees, which is at the lower end of its 70-85 specification. The arugula is alive, but is not bursting out of the tray. As I say so often when it comes to the greenhouse, "We'll see what happens." Dec. 29: He's dead, Jim. The arugula is frost damaged so I'm ending that experiment. It got down to 23 degrees inside the mini a couple nights ago. Even though that was 15 degrees warmer than the rest of the greenhouse and 30 degrees warmer than outside, and even though it was on a heat mat, it was not enough to prevent the arugula from getting slammed.

I picked a few carrots (which look good) and beets (which do not).

And finally, we have a broccoli head. It's only about an inch across, but it is there. The coldest it has gotten inside the greenhouse was 16 on Dec. 1 (outside -1). This plant is not exploding with growth, but it is slowly plugging away. I'm guessing if we get a week of sub-zero, that will put an end to it.