Friday, June 3, 2011

Seedling Exercise #1

This will be the first in a series of reports over the next few years to follow the progress of some seedlings. I received a flask from Casa de las Orquideas last Fall, and deflasked the seedlings October 21, 2010, keeping 60 of them. After spending the last 7.5 months growing in compots followed by cell tray, I moved each into its own 2.5” (6cm) pot . Of the 60 starting seedlings, only 53 (88%) remained for potting up. Given this denominator value, I don’t think the loss rate is bad.

Potting up means an opportunity to look at the seedling roots. As you can see, the seedling on the left has very little root growth; whereas, the seedling on the right has a much better root system. Why is this?

Well, almost all of the seedlings were potted up from the compots into the cell trays in a coir/expanded clay pellet mix. However, I ran out of the coir before I could finish the seedlings, so I potted up the last few in sphagnum moss instead. The seedling on the left with essentially no roots was grown in the sphagnum.

The seedlings clearly varied in their habit, even though they’ve been grown side-by-side. So, I decided to measure three parameters: height, number of leaves and longest leaf.

Seedling height ranged from 4 to 16.5cm.

Leaf number ranged from 2 to 10.

Longest leaf ranged from 6 to 20cm.

Seedling height and longest leaf correlate positively, that is to say, the shortest leaves tend to be in the smallest plants, and the longest leaves tend to be in tallest plants. This may seem intuitive, but I went through the exercise because some seedlings had several leaves and appeared squat; whereas, others with several leaves appeared tall and narrow.

Based upon these parameters, I kept the top 50% of the longest leaf (at least 10cm), resulting in 32 seedlings to continue growing. Below you can see a clear difference between the selected plants (on left) and those that will be culled (on right).