In the past I’ve worried a lot about transplant shock. When you remove seedlings from a seed tray, separate them and then stick them in the ground, they really suffer. So much so that I’ve often wondered if it wouldn’t be better to transplant them en masse, transplant them in bunches or even leave them to struggle on in their overcrowded pot.
Yesterday was one of those startling examples of exactly what transplant shock does to seedlings. Some of the tomato seedlings from the pot of seeds sown in mid-August were planted out on September 16th. The rest were left untouched in the pot until yesterday when I transplanted 6 more of them. In the photo it is easy to compare the seedlings planted yesterday (6 plants in 2 rows on the right) with 2 seedlings from the same sowing which were planted 6 days earlier (2 tiny plants at the back on the left). Basically, those that weren’t transplanted doubled in size in their pot in a week compared to the transplanted mob which have been dormant. Yikes!
But I keep reminding myself that the shock does pass and that plants separated do a lot better than those left crammed in a pot together. I first learned this when I left lettuce seedlings in the pot they were sown in. It took about a month for the transplanted lettuce to outshine them but outshine they did.
A recent example of how transplant shock is overcome was when I planted out some flowers I’d grown from seed. A mix of Nigellas and Poppies made it into 2 separate pots. The first pot was planted with seedlings that I painstakingly separated. The remainder went in big bunches – dirt and all – into a hanging basket.
The seedlings that were individually transplanted had a major shock and were pretty much horizontal for a good week before they slowly sprang upwards. Those that went into the hanging basket enjoyed undisturbed roots and the seedlings suffered no transplant shock – they just kept on growing. 6 weeks later, the plants that had the worst transplant shock are miles ahead of those that suffered no stress. On the left are those that were individually separated and planted. On the right, the basket full of undisturbed mass plantings.
No flowers on either yet but, if I get any, I am certain I’ll get more from those I traumatised with transplanting.
Like those in the know say, that which doesn’t kill us makes us stronger. It looks like it goes for plants as well as humans.
An interesting side note – last year I found myself on a small local farm. The farmer said she had to go quite a distance to get seedling stock that was as small as she liked. She believed that transplanting more mature stock leads to longer shock (2 weeks versus 2 days was her theory) so she prefers tiny seedlings. I’ll watch my tomato plants to see if the plants that were transplanted younger end up producing earlier.
I also sowed more radishes, lettuce, basil and carrots yesterday. Radishes and lettuce because it’s always good to have some new ones coming up to replace the existing crop. Carrots just because (and they are good to sow in with the radish rows). I sowed basil because it’s the season and my previous sowings (2 in fact) have failed. I assumed my seeds were too old so I opened a new pack. Basil has been easy for me to grow in the past and I count on a plentiful supply through summer and autumn.
Laura Rittenhouse's Gardening Journal 
Very interesting Laura, I sometimes have used toilet rolls to reduce transplant shock and found the plants actually did not do so well – maybe they need that shock to strengthen then – never thought of it that way. I planted out some more lettuces int he hopes that this lovely weather we have been having continues on a little bit longer before the humidity sets in.
My lettuce is going really well. Obviously Sydney spring is good for leafy greens. I’m not so confident about Northern Australia wet season being as kind. Good luck.