Sometimes, being a gardener can be painful. Your back often aches, your carpel tunnel can flare up, the rose from your grandmother’s garden can die, or your favorite tree can succumb to disease. Another of these painful days, is the day you must thin your seedlings. After weeks of babying, watering, fanning, heating, and cooling, you are suddenly forced into a dark corner, one where you must actually pick off one of your own baby plants. It feels like infanticide and reminds me of that gut retching moment in the novel, ‘Sophie’s Choice’, when the main character is forced to choose which of her children will live, and which will be gassed in the concentration camp. Okay, its not THAT bad, but it is extremely difficult and a day I always dread.
Then why do it? For the health and well being of your seedlings, it’s essential. Without thinning, those little plants can easily succumb to disease due to lack of air movement from overcrowding and, they often grow stunted and lame from being forced to compete for light, nutrients, and water. Trust me, I have tried to get away without thinning, and it has never turned out well for me or my veggies. You will know it is time to thin your seedlings when they are 3 – 4 inches tall and have their first set of true leaves.
Above are my seed trays of broccoli, cabbage, and chard before they have been thinned. They are overcrowded, lanky, a few planting cells are empty, and the stems aren’t as green as they could be. Grab some sharp scissors because it’s time to get down and dirty.
You could pull the seedlings gently out by hand one by one, but this is tricky to do. The roots of the seedlings are often entangled, so when you pull one, they all come out. Instead, I like to use a pair of scissors to cut the plant at soil level, which keeps me from disturbing the healthy starts roots.
To begin, look for stems are lanky and leaning, stems that may be damaged, seedlings that are runts, and plants that have discolored or unhealthy looking leaves.
As you move along, if you come across an empty planting cell, you can transplant an overcrowded seedling, into the empty one. Using your fingers, pinch down into the soil, grabbing the roots and the stem. Gently pull the seedling out of the soil and place it firmly into the empty cell. Problem solved and one baby saved from the scrap pile.
As you thin, it is important to note that you do not always want to keep a seedling simply because it is the tallest of the group. The seedling you choose to keep should have the sturdiest, greenest stem, and the healthiest leaves and new growth emerging. Like the healthy middle guy in the picture below.
When finished, there should be one plant per cell, and they should be the best and greenest of the group.
I do like to keep two cells with 2 plants for another couple of weeks. That way, if I do lose a start, I have a back up I can transplant. When I have finished, I am left with a very nice sized bowl of sprouts which my guinea pig, Brownie, is going to down in 2 minutes flat.
On a side note, my kiddos walked in on me thinning my plants and were horrified. As a teacher, I do love a teachable moment and this is my moment. To show my real babies the effect overcrowding has on seedlings, we are going to conduct a little experiment by leaving one cell with all of the sprouted seedlings, one cell with 2 seedlings, and comparing them to the thinned cells. I’ll keep you posted on our experiment’s findings as the growing season progresses.
The torturous thinning session is finally over. Time to give the baby plants a drink of water and tuck them back under the grow lights. After all that heartache, I think a glass of wine may be in order for me as well. Good luck gardeners and remember, thinning seedlings may be the dark side of gardening, but you will receive just rewards in the end.