First, brown patch findings. I started to brush the fluffy light material aside from center of #17, which was watered yesterday and a plastic cup placed on top of it. As I kept removing the wet soil I eventually started to get into dry and then very dry soil. Eventually I got to the seedling. It looked as healthy as I placed it a week ago, only with no additional apparent growth.
November 11, 2012 #17 one week old
I did another digging on #18, with identical result. Given that these two were the most watered samples, I expected same result with the rest of the patch. In fact, the rest of the samples that I checked were all dryer. The good news was that all looked nice and healthy, indicating that the amount of water in the soil was just barely enough to keep them alive.
The next thing I did was to push the top 0.5-0.75" of soil to sides from center until I either reached the top of seedlings or was deep enough that it should be pretty close to it. I poured about 20ml (3/4 oz.) of water directly in the formed cavity, waited two minutes for water to get soaked in and then pushed the soil from sides a bit on top. I did very little of soil on top, no more than 0.25"on visible tops of seedlings or none at all on those where I could not see them.
Water in the hole.
The major advice from the Internet users is to keep the top surface wet while volume underneath the seedlings dry. Since this material I am using absorbs water and keeps it extremely well very close to where it was applied, I decided to place plastic cups on all samples. The idea is to preserve the very top level wet as long as possible and do not poor too much water. I have a pretty good confidence that the seedlings now have a direct access to water, while material directly beneath them is mostly dry.
Now to the white patch. The CSI was brutal. Most of the samples with no visible parts above surface, and some with those signs have been pronounced dead. The toll looks as follows: from the October 28th planting, three seedlings died, while November 3rd planting claimed another three. Now six out of sixteen white tubes remain vacant.
From what I understand the major reason for white patch deaths was over-watering. Another reason for #11 and #12 deaths can also be attributed to the very dense (and wet) black soil. It was very apparent that the seeds got their stems that emerged from the seeds damaged. Since I had no idea what the "damage" would look like, here is a first hand account: the color of the stems changed from red-purple at the place of emergence from the seed as well as the white root on the tip opposite of the attached seed to gray. Another big sign was the thinness and apparent wrinkles of the emerged stems. Thin and gray - bad:
Gray and thin equals dead.
The gray and thin stems separated at the lightest touch from the seed casing. This was in stark contrast to the brown patch seedlings that were firmly attached to the light brown casings while being thick and having bright purple and white colors. I had no problem handling a couple of seedlings from the brown patch, while the white patch samples fell apart with a slightest touch. I am pretty sure I could bend the stems coming from the seeds on the brown patch and they would snap right back, judging by their healthy look, but I did not try.
In conclusion, the material used for growing seems to have a major effect on survival rate of the seedlings. It's as as easy to over-water as it is to under-water the Giant Sequoia seedlings when very different soil materials are used. The good news is that under-watering does not lead to a quick death.
My theory and prediction at this time is that the brown patch will look much livelier next weekend.
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