April 2011

[Johnny PhantomMember]

Hello Charles,

I notice in your April diary that you’ve got tomatoes coming on… can I ask what you do, if anything, to keep them warm? We’ve been struggling with ours… they’ve been on a heated bench whilst germinating – which has always gone really well. But, they’ve all gradually succumbed to what we think is a colder temperature when we’ve moved them off the bench.
We’ve read about people wrapping plants and benches in bubble wrap, and also, a friend (who grows a lot of tomatoes) lost a third one night, when the temperature changed.

Thanks,

JP

[charlesModerator]

 Hi JP

I still wonder about your compost because it sounds like you are having more problems than you should be. Can you post a photo of the plants here?

However it does certainly depend on the ambient temperature in your conservatory. But until today that should have been consistently high with the fine weather. Most of my tomatoes are still on heat (thermostat at 20C) but are about to come off to make way for potted on melons and cucumber, which are more in need of warmth. 

If I had the heated space I would keep the tome on it, just to have earlier and bigger plants, but they should tolerate cooler temperatures and then grow well on sunny days.

[Johnny PhantomMember]

Hello Charles,

Thanks for the reply.
As you know, we were trying the Fertile Fibre stuff, but we’ve subsequently switched over to West Riding, and have tried their Moorland Gold, seedling and their potting compost… with the same results. The tomato plants germinate beautifully, in any of the mediums. They last about a month, and then all go the same way – the seed leaves, wither and fall off, and then the true leaves (and any other leaves) all gradually turn pale and wither.
The first plants we grew (mid-Feb), in the Fertile Fibre, have actually been left in the modules outside since mid-March, and interestingly, they don’t seem to have died. If anything, the leaves that have survived (in a loose sense of the word) actually look quite nicely dark green!
The second plants we grew (mid-March) were started in WR sowing compost and moved into WR potting compost at the beginning of April. We moved them when the seed leaves started looking a bit pale, thinking that was a sign to get them into bigger pots. They lasted until the second week of April before the same symptoms started.
The third lot (end of March) were sown into WR sowing compost, and they’re still with us at the moment. We’ve moved some into WR potting compost (as we’ve been led to believe that it would be better to get them out of the sowing compost when the first true leaves appear), and into two different size modules (to see if that makes a difference). Some of the original plants have been left in the sowing compost, at the moment. So, we currently have three different trials.
One thought occurs to us – is it simply better to start tomatoes with the potting compost rather than worrying about starting with the sowing compost?
I do have some pictures, but I can’t work out how to get them on here. I can email them to you, if that’s ok?
I think the conservatory has a tendency to get overly hot, and so we’re also wondering whether it might have something to do with airflow – lack of, or insufficient air movement – in the conservatory.
To tie this in with the other thread, we’re havng almost exactly the same problems with our brassicas!
Your brassicas have been in full sun on the bench for three or four weeks – we’ve tried putting ours outside, as leaving them on the bench was resulting in them all dying off.

Thanks again for all your help,

JP

[charlesModerator]

 Hi Johnny

Yes please email some pics, at low res because our broadband is slow. It all sounds bizarre. I use seed compost for basil and lettuce only. Your tomato seed leaves (cotyledons I presume) should not be turning pale. I shall wait to see. Too little air could be an issue.

[welshgrassMember]

Hi guys,

Just found this thread and thought I’d add my views. We grow around 400 tomato plants a year using Fertile Fibre seed compost and then transplanting into Fertile Fibre potting compost. We sow with bottom heat and use a mist bench to raise the seedlings. Yellowing rarely happens before we pot on from modules into 9cm pots. We usually get near 100% germination and the plants stay in 9cm until point of sale.

The commonest problem with using Fertile Fibre is that people use it straight out of the bag. It must be well fluffed up before use and not compacted subsequently. Also heavy watering can cause a crust to form (particularly with the seed compost), so go easy as overwatering Fertile Fibre is another common problem.

We use Fertile Fibre extensively and bar one problem batch (see my reply to that thread) have had no problems in more than eight years. Because of those problems we trialled Fertile Fibre against Com Vert this year. See pictures at http://www.gwynfor.co.uk/composts.html for the results of this trial.

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