Saturday, 4 April 2015

My Tomato Experiment

Thursday’s lovely spring weather didn't last into Friday which was dull and wet.

This probably isn't much of an experiment to most of you out there but for me one of the main problems of sowing my tomato seeds early is how do I grow them on. Getting them to germinate under our indoor growlight doesn't normally pose any problems. It’s once these seedlings are ready to transplant that my problems start. I consider it far too cold for these plants to go out into our unheated greenhouse when the temperature in April can drop down to or even below 0°C or 32°F. Not very conducive for growing young tomato plants.

So I leave my sowing a little later with the hope that by the time the seedlings are ready to transplant temperatures in the greenhouse will be a little bit warmer. This means I have to see lots of tomatoes ready for picking on social media whilst mine are still green. I thought I might try to grow a couple of early plants with a main crop to follow.
 As an experiment I sowed 4 seeds of Cherry Fountain and Baby Boomer on 15 March and these were left under our indoor growlight to germinate. Even under the growlight the seedlings had grown a little bit leggy. I didn't consider this too much of a problem as they were transplanted to the depth of their seed leaves when I potted them on.
My eight seedlings were all potted on on Tuesday 31 March. I hadn't room for all 8 pots of seedlings in my home made solar reflecting propagator so the experiment was amended a little bit to see how 4 seedlings grown indoors would compare with 4 seedlings left to do their best in the cold greenhouse. I’ll keep a close watch on the coldest greenhouse temperatures to see how these 4 plants do.

I've been as kind as I can to them and given them the added protection of a propagator lid. If the forecast was for an extremely cold night with a severe frost I might take pity on them and bring them into the porch.
They didn't look that impressed after they’d just been transplanted but I’m hoping they’ll recover after a couple of days. Will they provide us with a few early tomatoes or will my later sown seeds catch them up? Time will tell. 


  1. that`s a lot of work Martyn hope it comes to fruition in the summer with some juicy tomatoes

  2. Damn social media! I'll be interested to see how the greenhouse ones get on, I usually end up putting mine in an unheated mini greenhouse quite early because I run out of windowsill room. I saw an interesting experiment in a gardenening magazine a few weeks ago showing maximum tomato crops from tomatoes grown two to a gro-bag and watered once every three days. I think I might try that with some plants this year to see if it works for me too. These little experiments are endlessly fascinating.

    1. I saw a recommendation this week for two tomato plants only to a grow bag. Can't remember where though. For the last couple of years I've used those extra large growbags and I've noticed that the roots don't entirely fill the bag when the bags are emptied at the end of the season. So I assume there's enough compost for three plants but maybe more space above is the key to success. Look forward to seeing how you get on with two to a bag.

  3. My tomatoes are always sown in an upright plastic cold frame (no window ledges in my house) in late March or early April and although germinate slower than in a heated place, still mostly make it in a few weeks whatever the temperature. Then they get potted on and continue in the frame until planting out. I've had them out there in the frame from start to finish in gales, frost and snow - they are tougher than expected.

    1. My tomato seeds are normally germinated inside but from then on spend their life in our unheated greenhouse. Not too different from you. We've never lost any seedlings but they grow slowly or not at all in any very cold weather. I'm trying for some earlier tomatoes than usual so I'll have to wait and see if I have any success.


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