Gard, a pH of 6 is ideal for toms. They prefer it slightly acid. A homemade mix might well explain some nutrient deficiencies, but I haven't seen those sorts of lesions before as a result of, especially, magnesium deficiency.
In terms of limiting the chances of fungal problems - if you don't want to spray, you just have to adopt all the housekeeping practices mentioned above. And, in a greenhouse, most of all, great ventilation.
You will never escape fungal spores. They're airborne, they're everywhere, and effectively invisible. All you can do is create an environment that gives them the least sympathetic conditions.
I guess I'm hedging my bets with my 'plan of action', i.e. using your advice to treat a possible fungal infection (esp re ventilation), and the epsom salts for the suggested magnesium deficiency - hopefully, it can't hurt?
Re spraying for fungal infections, what do you spray with, when, how etc, etc?
Looked and sounded like a magnesium deficiency to me, with a secondary problem once the leaves were damaged by the deficiency - but it is very hard to tell definitively from photographs.
Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
No, spraying for the deficiency won't hurt. I think it's about 20g ES per litre of water. Spray in the mornings to let the foliage dry out during the day.
Spraying against fungal problems has become a tad controversial these days. Most of the common fungicides are chemicals and many are reluctant to use them and with good reason. They poison foraging insects amongst other things.
The most common organic treatment is a copper sulphate spray. Very popular here in Italy. You see tom plants everywhere with bright blue leaves. But, while it's organic, it's also a metal, it can eventually build up in the soil, and doesn't do foraging insects much good either. I don't use it because I don't like metal building up in the soil.
The very best treatment I ever came across - and used when I was back in Australia - was a chlorothalonil-based spray. It comes under various brand names - Daconil, Bravo, etc. It's synthetic, a chemical, but harmless to foraging insects. It will kill fish if you pour it into a fish pond. So I didn't pour it into any fish ponds. It's very widely used in the US - the home of heirloom tomato growing - and even by many organic growers. They acknowledge that it's not organic, but (a) it doesn't harm the garden wildlife; and (b) it's stunningly effective.
Problem is, it's hard to come by outside the States for domestic use. In fact, in Australia, it was only available in bulk for farm use. So a group of us tomato growers all chipped in, bought a container, and divided it up. It worked brilliantly.
A week or so ago someone posted in this forum about spraying with milk against fungal problems. Some people do, and swear by it, but there's no scientific evidence that it works. At best, it's thought that the milk might amend the pH of the leaf surface to a figure less sympathetic to the spores.
The principle of spraying against fungal problems isn't that you kill the spores. You can't. You spray preventively - before the spores arrive - and coat the leaves (on both sides) efectively stopping the spores getting a grip. Normally you would start spraying just after planting out and about once a week thereafter. If it rains, obviously, you have to respray. It's not always failsafe - though I found the chlorothalonil was - but it's the best you can do in terms of taking positive action.
I don't spray here in Italy but only because I can't get chlorothalonil here. I just do all the basic housework and hope for the best. I get Early Blight and Septoria Leaf Spot - the two most common fungal problems in the home garden, and they're pretty inevitable - but nipping off affected leaves as soon as the symptoms appear keeps things under control.
I was just flicking through the June 2012 issue of 'another large gardening organisation's magazine' - (I don't know if mentioning the name of the organisation/ magazine is an infringement of some kind, so I had better not use them) and on page 2x there is a picture of a tomato leaf affected by magnesium deficiency. It is identical to the leaves on my tomato plants during one stage of this progressive problem. So thankfully, I at least know for sure what the problem is.
Hi Italophile. There is still a mystery! My outdoor tomato plants (identical plants, compost, pots, watering, feeding etc, etc) don't have this problem - Why?
The article I mentioned above talks about using Epsom Salts to the soil, and later, as a foliar feed - doesn't mention if you can/should use both at the same time. Any ideas?
For soil treatment it mentions the amount of ES, but not if this is applied dry to the soil & then watered in, or applied as a liquid solution - if the latter, it doesn't mention what the mix ratio should be. Any Idea?
That's why I think the problem has been as much disease as deficiency. Or in fact more disease than deficiency. If it were more deficiency, all the plants in the same compost should suffer the same problem.
Out of interest, could you post that recipe you used for the home-made mix?
ES is usually applied as a foliar spray. The leaves absorb the ES, a faster-acting process than going via the roots, whereby the roots first have to absorb the product before distributing it. Mix up 20g ES/litre of water and spray once a day for a week or 10 days and see how things look.
The compost mix, using a 1.5 litre pot, is in the following ratio:
2 x J. Arthur Bower's multi purpose compost.
2 x sifted garden compost (a mix of garden and food waste [potato peelings etc] fully organic - I don't use anything on the garden except on my pots - Miracle Grow, or Tomorite, used as per instructions).
2 x sifted basket compost (last years).
2 x perlite.
I also add in 2 scoops (about a teaspoon per scoop) of water retaining crystals.
I have used exactly the same mix on all of my pots & baskets (whether flowers or veg) and with the exception of the greenhouse tomatoes, I don't have a problem.
Well, that's a good basic mix. It shouldn't lack magnesium in any way. Cutting back on the feeding - Tomorite is very high in potassium, which can thwart the take-up of magnesium, as Dove suggested - should be a big help.
Toms outdoors in the ground are less prone to these sorts of nutrient conflicts - though not immune to them - because the roots, in the ground, can effectively find what they need somewhere in the soil around them. Roots in containers are trapped and can only access whatever you give them. On top which there's the problem of nurtients leaching from the mix with every watering.
That said, there's also a leaf mould problem, and that is greenhouse-specific. It's why the outdoor plants are fine. I think you probably ran into a perfect storm of fungus and nutrient deficiency, Gard.
Posts
Gard, a pH of 6 is ideal for toms. They prefer it slightly acid. A homemade mix might well explain some nutrient deficiencies, but I haven't seen those sorts of lesions before as a result of, especially, magnesium deficiency.
In terms of limiting the chances of fungal problems - if you don't want to spray, you just have to adopt all the housekeeping practices mentioned above. And, in a greenhouse, most of all, great ventilation.
You will never escape fungal spores. They're airborne, they're everywhere, and effectively invisible. All you can do is create an environment that gives them the least sympathetic conditions.
Thank you once again Italophile.
Great news re the PH level.
I guess I'm hedging my bets with my 'plan of action', i.e. using your advice to treat a possible fungal infection (esp re ventilation), and the epsom salts for the suggested magnesium deficiency - hopefully, it can't hurt?
Re spraying for fungal infections, what do you spray with, when, how etc, etc?
Looked and sounded like a magnesium deficiency to me, with a secondary problem once the leaves were damaged by the deficiency - but it is very hard to tell definitively from photographs.
Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
No, spraying for the deficiency won't hurt. I think it's about 20g ES per litre of water. Spray in the mornings to let the foliage dry out during the day.
Spraying against fungal problems has become a tad controversial these days. Most of the common fungicides are chemicals and many are reluctant to use them and with good reason. They poison foraging insects amongst other things.
The most common organic treatment is a copper sulphate spray. Very popular here in Italy. You see tom plants everywhere with bright blue leaves. But, while it's organic, it's also a metal, it can eventually build up in the soil, and doesn't do foraging insects much good either. I don't use it because I don't like metal building up in the soil.
The very best treatment I ever came across - and used when I was back in Australia - was a chlorothalonil-based spray. It comes under various brand names - Daconil, Bravo, etc. It's synthetic, a chemical, but harmless to foraging insects. It will kill fish if you pour it into a fish pond. So I didn't pour it into any fish ponds. It's very widely used in the US - the home of heirloom tomato growing - and even by many organic growers. They acknowledge that it's not organic, but (a) it doesn't harm the garden wildlife; and (b) it's stunningly effective.
Problem is, it's hard to come by outside the States for domestic use. In fact, in Australia, it was only available in bulk for farm use. So a group of us tomato growers all chipped in, bought a container, and divided it up. It worked brilliantly.
A week or so ago someone posted in this forum about spraying with milk against fungal problems. Some people do, and swear by it, but there's no scientific evidence that it works. At best, it's thought that the milk might amend the pH of the leaf surface to a figure less sympathetic to the spores.
The principle of spraying against fungal problems isn't that you kill the spores. You can't. You spray preventively - before the spores arrive - and coat the leaves (on both sides) efectively stopping the spores getting a grip. Normally you would start spraying just after planting out and about once a week thereafter. If it rains, obviously, you have to respray. It's not always failsafe - though I found the chlorothalonil was - but it's the best you can do in terms of taking positive action.
I don't spray here in Italy but only because I can't get chlorothalonil here. I just do all the basic housework and hope for the best. I get Early Blight and Septoria Leaf Spot - the two most common fungal problems in the home garden, and they're pretty inevitable - but nipping off affected leaves as soon as the symptoms appear keeps things under control.
I was just flicking through the June 2012 issue of 'another large gardening organisation's magazine' - (I don't know if mentioning the name of the organisation/ magazine is an infringement of some kind, so I had better not use them) and on page 2x there is a picture of a tomato leaf affected by magnesium deficiency. It is identical to the leaves on my tomato plants during one stage of this progressive problem. So thankfully, I at least know for sure what the problem is.
It's been a fascinating couple of days, Gard. A good garden mystery is always fun - except when you're on the receiving end!
The article I mentioned above talks about using Epsom Salts to the soil, and later, as a foliar feed - doesn't mention if you can/should use both at the same time. Any ideas?
For soil treatment it mentions the amount of ES, but not if this is applied dry to the soil & then watered in, or applied as a liquid solution - if the latter, it doesn't mention what the mix ratio should be. Any Idea?
That's why I think the problem has been as much disease as deficiency. Or in fact more disease than deficiency. If it were more deficiency, all the plants in the same compost should suffer the same problem.
Out of interest, could you post that recipe you used for the home-made mix?
ES is usually applied as a foliar spray. The leaves absorb the ES, a faster-acting process than going via the roots, whereby the roots first have to absorb the product before distributing it. Mix up 20g ES/litre of water and spray once a day for a week or 10 days and see how things look.
The compost mix, using a 1.5 litre pot, is in the following ratio:
2 x J. Arthur Bower's multi purpose compost.
2 x sifted garden compost (a mix of garden and food waste [potato peelings etc] fully organic - I don't use anything on the garden except on my pots - Miracle Grow, or Tomorite, used as per instructions).
2 x sifted basket compost (last years).
2 x perlite.
I also add in 2 scoops (about a teaspoon per scoop) of water retaining crystals.
I have used exactly the same mix on all of my pots & baskets (whether flowers or veg) and with the exception of the greenhouse tomatoes, I don't have a problem.
Just going out to spray the leaves.
Well, that's a good basic mix. It shouldn't lack magnesium in any way. Cutting back on the feeding - Tomorite is very high in potassium, which can thwart the take-up of magnesium, as Dove suggested - should be a big help.
Toms outdoors in the ground are less prone to these sorts of nutrient conflicts - though not immune to them - because the roots, in the ground, can effectively find what they need somewhere in the soil around them. Roots in containers are trapped and can only access whatever you give them. On top which there's the problem of nurtients leaching from the mix with every watering.
That said, there's also a leaf mould problem, and that is greenhouse-specific. It's why the outdoor plants are fine. I think you probably ran into a perfect storm of fungus and nutrient deficiency, Gard.