Too Cold For Tomatoes?

The tomato plant is not doing well. All seemed to go well at first. Then leaves started rolling and growth became slow and stunted. Although there are a few flowers and fruits, things should be much better. They started to go wrong after I saw greenfly feeding on the stems. The growing tip rolled up like a clenched fist within days and never recovered.

SAME AS LAST YEAR
This is exactly what happened last year, the only difference being I have not detected any blight (last year's plants had to be destroyed).

These normal leaves are from a cutting of 'Outdoor Girl', given by a neighbour. These plants (he gave me two) have defied all neglect and seem insistent upon forming normal plants.

STILL NO WISER
The fact that 'Outdoor Girl' is a reliable outdoor variety indicates I have been 'flogging a dead horse'. 'Alicante' and 'Ailsa Craig' (last year's variety) just will not grow in my garden, probably because it is too cold and draughty. Although, of course, the greenfly could have brought a virus? I'm still no wiser.

Blight Danger

High temperatures (25 deg C) and humidity forecast this weekend. Best get tomato plant sprayed with 'Dithane' (mancozeb - a contact fungicide). But there's a problem in wet weather - it tends to wash off too quickly before temperatures high enough for blight to be a danger. This is what happened to tomatoes last year.

Tomato Surface Roots

After carefully scraping beneath compost surface, I found this root about 2cm (3/4 inch) down. Didn't want to disturb it more than necessary, so could not tell if it had come up from below or had grown from top of stem (seems more likely). Still, it means things are still going to plan - a miracle in itself.

Will continue with light waterings (1 pint per gallon of compost) when top of compost just starts to change colour. Should encourage good root system.

Although there's a truss of flowers forming, these are not yet open. Will only step up watering and begin feeding once first tomatoes have set and are about pea-size.

Hopefully things will speed up with recent warmer weather.

Tomato Blight Protection

Sprayed tomato plant with contact fungicide 'Dithane' (80% w/w mancozeb) to protect against tomato blight (Phytophthora infestans). Still a little early - blight has always attacked my tomotoes in August. As outlined last year (see 'Tomato Blight Update', 26 August), it requires '. . . consecutive 24 hour periods, each with a minimum temperature of 10 deg C (50 deg F) and each with a minimum of at least 11 hours where the relative humidity is 89 per cent or more'. i.e. hot muggy weather.

Contact fungicides are effective over a much wider range of diseases than systemic ones, but must be applied BEFORE disease spores come in contact with plant. They work by preventing spore germination on plant surface and need applying every two or three weeks. Systemics prevent spore germination but also block active metablolism inside plant - so should also be effective AFTER infection has occurred. See also: 'How Fungicides Work'.

Not sure if 'Systhane' (myclobutanil) can be used on tomatoes. It can be a bit fierce. Tested on a single leaf, which seemed to change colour, though not sure if this was due to chemical or to other causes. Bordeaux mixture (copper sulphate) is also effective on potatoes, though again not sure if it can be used on tomatoes. Does anyone know?

Leggy Tomato Plant First Watering

Gave a pint of water to tomato plant in gallon pot today. Don't want to give too much till roots come up to surface. Recent rains have helped but not enough. Compost dry down to 5cm (2 inches). i.e. no water visible when squeezed between thumb and forefinger; plant been going limp in hot sun, but recovering overnight.

Foliage now darker in colour, so roots have found new compost after re-pot. Plant seems to be growing quite well, so far. First truss now has some unopened flowers.

Tomato Plant: No Water For 5 Days

Haven't had much luck with growing tomatoes. This is the third try after two disasters (tomato blight) caused by weather, several years apart. Thought it might be different this year . . .. Perhaps not.

Sure enough, true to form, the weather turned on me. Within hours of potting up, a cold wind arrived, temperatures were plunging towards 14 deg C (57 deg F) and heavy rain clouds were forming. It could only happen to me.

As outlined last week, further wetting of the compost could have been fatal. So moved plant to dry spot close to house. Not much sun there. But at least it was warmer and more sheltered. After staking stem to a small cane to prevent it breaking off in wind, went away for a few days, full of hope.

Expected leaves to curl up, or turn blue - or both. Not so. Plant doesn't look too bad and actually seems to have grown a little .... Astounding . . .. The compost is just about right for growing - surface turning a nice light shade of brown. Moved plant back to a draughty but sunny spot - the only one available.

WATERING
No water given yet. Should encourage roots to spread out in the compost.Don't expect to water for a while yet; depends on weather.

Re-Potting A Leggy Tomato Plant

This tomato plant is a bit leggy, to say the least. So I'm re-potting it into a gallon (20cm deep) pot, burying the lower nodes (after removing leaves) beneath the compost upto the red line. This should keep the plant more stable and allow some adventitious roots to grow from the stem, allowing greater access to food and water (see 'How Adventitious Roots Can Supercharge Growth').

After removing the lower leaves, I set the plant in the bottom of the pot and added medium-wet (see 'Wetness Of Compost') multi-purpose compost*.

Although not a good idea, I'm going to put the plants outside. The weather is cold and windy and the stems are moving around but, provided they don't break, this should strengthen them. With the plants hardly hardened off (they should be gradually acclimatised), all we need now is some frost.

* Because the whole plant is sitting nearly on the bottom of the pot with a relatively tiny root system, it is important not to drown the plant by adding too much water too soon. Remember that any water added will percolate down to the base of the pot. This is not normally a problem when the plant is at the top of the pot.

Make sure there are unrestricted drainage holes (these will also facilitate air entry, helping the roots take up water and nutrients) in the base of the pot; and delay further watering as long as possible, so the roots will go out all over the compost** seeking water.

** See also 'Potato Feeder Roots Fan Out In All Directions' to see how roots spread out through soil or compost.

Tomato Plants Destroyed

'Dithane' treatment does not seem to have contained the tomato blight, which was gradually extending over all the tomato plants. So these have now been destroyed and the compost soaked in bleach. I will let it weather over winter and then apply it to the rose bed next year.

I know I shouldn't do this. But I cannot bring myself to waste so much compost.

Tomato Stem Bottleneck

Apart from the suspected blight, the reason the fruits were so slow to swell on the tomato plant might be something to do with the stem thickness at the base of the plant.

This photo (sorry, not a very good one) shows how it looked at the beginning (the thin part) and how it looked once it was cared for (the thicker part). I am surprised at this. I thought it would have thickened all the way down. Apparently not. But it does seem it could be at least a part of the problem.

Tomato Blight Update

Further downpours have produced more blackened tomato leaves: almost certainly blight. Leaves were immediately removed and burnt.

I am not absolutely certain the problem is blight, but it fits. Both potato and tomato blight are caused by the fungus Phytophthora infestans.

The RHS 'Pests and Diseases' outlines the necessary conditions as:

'. . . consecutive 24 hour periods, each with a minimum temperature of 10 deg C (50 deg F) and each with a minimum of at least 11 hours where the relative humidity is 89 per cent or more'

I am not sure whether the 'Dithane' has stopped it or not. Of course, I should really have destroyed the whole plant. But there seems little point, since it must have arrived in the air; and if I grow more tomatoes next year, I will choose a blight-resistant variety (nevertheless, I will still give everywhere a good disinfecting, before then).

I suppose I am reluctant to lose the few fruit which are there. I just want to wait and see how things develop.

Tomato Blight?

I think the black blotch on this tomato leaf is tomato blight. I first noticed it three days ago, but didn't spray immediately as I should have done because I seem to have done nothing but spray this and that over the past month or so. This is why I recently reported the doom and gloom: It's not the pests and diseases which are causing it, but the constant use of chemicals. I don't like using them, and never have; I am all the time seeking ways to avoid them.

Up till this year, I had got my garden relatively free of these problems (I'll explain how later). But I suppose it's the influx of all the new stuff which is causing the trouble. Now am having to start all over again.

I had thought that the tomatoes were beyond hope. I didn't believe those who told me that some varieties of tomato rolled their leaves naturally. And I don't know why I didn't do a 'Google' search for tomato leaf roll. However, I did one yesterday, and found plants which resemble mine. Apparently the problem is stress-caused.

This bottom truss of the problem plant has 26 set fruits (some are still tiny). They had been hanging around, not growing, but have recently started to swell. There are set fruits on the truss above, as well. And we have already seen that one truss has been discarded due to 'dry set'.

To be honest, I had more or less given up on the tomatoes; I had taken my eyes off the ball. Now I have decided to take interest once more.

We can leave the moral issues of whether spraying is necessary or not. This blight is the same sort of thing which caused the dreadful Irish Potato Famine; IT DEFINITELY NEEDS NIPPING IN THE BUD, STOPPING IN ITS TRACKS.

Have sprayed again with 'Dithane', probably too late. I am now monitoring the situation very closely. Will keep you informed.

Getting the Blight Protection

Recent hot humid conditions ideal for the fungus diseases 'tomato (and potato) blight'. Sprayed tomato plants with 'Dithane' as a precaution. The fruit can still be harvested, when it appears.

Tomatoes Roll Their Own

As you can see, I'm still having trouble with the original tomato plant. A tomato grower told me that rolled leaves are a sign of health, especially in young plants. I don't believe it - not in these, anyway.

However, tomatoes do roll their leaves when they are too cold (Cold? Come to think of it, mine do have a bluish tinge - I Wonder. . .. It's definitely not the warmest of spots). Yet the weather hasn't been particularly cold. And 'Ailsa Craig' can be grown outdoors. And why are the younger side-shoot cuttings doing so well, without any curled leaves - even in the same sort of pot? Another mystery.

The good news is that the second truss has set some fruits, which are starting to swell. Hurray!

Dry Set Tomatoes

Not having much luck with the tomatoes. These young fruits have been like this for about a month now, set without further growth. This is a condition called 'Dry Set', caused by too little humidity and too high temperatures at pollination (recent hot, dry weather).

It looked like a good first truss, too. Cut them off to divert energy to rest of plant. What next?

Out With the Old

Couldn't stand looking at stunted tomato plant any longer. Hoofed it out and replaced with one of side-shoot cuttings taken from same plant (removed before problem occurred). As you can see, roots look O.K .- Not fantastic, but O.K (i.e. white, not brown, with some growth and thickening).

Problem must be either weedkiller or a virus. By placing cutting in old compost, should tell us whether compost is suspect (planted the other of the two cuttings in new compost).

Tomato Problems

Things not good with tomatoes. The stunted plant was originally the better of the two.






This curled shoot tip is a sign of weedkiller damage. Roots have grown right down and out through holes at bottom of pot. Must have picked up some weedkiller from cracks in flags. Strange thing is, I don't remember using any weedkiller there. I never do. Another mystery.

I took a cutting from a sideshoot, which has now rooted. But I think it is too late to be of any use. Wouldn't fancy eating tomatoes off this plant, even if it recovers. Will keep it a while longer to see what happens.

Removed protruding roots and placed both pots on a plastic bin liner. Should have used one before. But they soon make everything look untidy.

Good news is that the better plant is really starting to grow now, after its bad start, weatherwise.

P.S. Tub insulation works a treat. Compost really cool, even in mid-day sun

Super Cool Tomatoes

Yes, I know: It looks awful. But I like it. No I don't - But does it really matter if it works?

Of course, I cannot yet answer that in the affirmative - it is far too early - and the summer has suddenly disappeared. But we should soon find out. I was so convinced it would actually work that I did both pots, instead of leaving one as a control.

In case you haven't yet guessed its purpose, can I just say that it is not so I can admire myself as I do the watering. No. The idea is to keep the compost temperatures super cool in hot weather. Do you remember that?

Roots need far more oxygen as the temperatures rise. And because more carbon dioxide is given off by respiration in the soil, the situation can become serious and impede growth.

But water loss also increases dramatically with temperature. Keeping things cooler conserves it.

The scrumpled newspapers on the top should allow air and water passage, whilst providing insulation. And aluminium foil is a great reflector, thus evening out the diurnal (day and night) temperatures. Brilliant. I really surpass and amaze myself at times.

But, seriously, it is quite common to find hot sun literally boiling the roots of plants kept in black plastic pots. Dark colours absorb far more heat. And if white pots (these are not too good because they allow light to get to the roots) lower the compost temperatures by about 4 deg C compared with normal colours, I cannot see how this could fail.

Clay pots are good for keeping plants cooler, but need more watering.

Feeding Tomatoes

Gave tomatoes 5mls of 'Phostrogen Plant Food' between them, in 4.5 litres (1 gallon) of water. A few of the flowers have now set, though it is still rather early. But I wanted to give them some water and feed to get some leaf growth.

When I look at everyone else's tomatoes, I feel quite ashamed; even though I know that too much leaf growth is not a good thing. But mine do look positively scrawny in comparison.

Apart from this, the tomatoes have not been watered since planting out, apart from rainfall. So much for developing a deep root system. It is proving difficult to dry them out.

If I let them dry out with the fruits on them, it will cause splitting. But it might be worth sacrificing (they can still be used) some fruits to get deep roots, even at this stage.

Potted Tomato Plants

Tomato plants have been potted out, over 10 days ago, into 30 cm (12 inch) pots of multi-purpose compost to which vermiculite has been added to increase porosity.

They have hardly made progress since purchase, mainly because it has been too cold. The suspected root rot has not materialised. But it takes plants quite some time to get over a bad start (they had been neglected).

As you can see, there is not much leaf. And it is apparently dangerous to give feed too early (which would develop the leaves) in case it stops flowering. Problems, problems.

I have not watered them since planting, although there has been considerable rain. I want to keep them dry to develop the roots. These should go searching for feed and water (there is some feed in the multi-purpose compost). I intend to leave them until they are wilting before watering with 'Phostrogen'. Well, maybe till just before wilting, if I can judge that.

In other words, I am treating them just the same as I would a flowering plant, which, of course, is what they are. We still want lots of flowers. The only difference is that we also want juicy fruits. All this is controlled by watering, as we shall no doubt later discover.

More New Kids

It's no use. I just can't face all those lettuce (most of them have taken) without some tomatoes. So, against my better judgement, I picked up two 'Ailsa Craigs', the last two left in the nursery (I only wanted one, but I couldn't leave the other).

When I got them home, I could see why no-one wanted them. I suffer from this rare kind of purchasing blindness. I just cannot see faults whilst someone is stood over me (I suppose it might be like the publishing blindness I suffer with this blog - I can't see any faults until it is published).

Apart from the fact that they have been neglected (as seen by the dry roots showing through the base of the pot, the elongated shape and the pale lower leaves), I was alarmed to spot this brown base on one of the plants. It looks suspiciously like root rot.

However, as you can see, the roots look quite healthy (they are white, not brown). And the brown base of the stem is firm, not soft. So we might just get away with it.

Re-potted them into 11.5cm (4 1/2 inch) pots of ericaceous (lime-free) compost.

Did not water; compost was moist enough for now.