Author Topic: Tomato blight protection? (Read 9334 times)

lewic · « **on:** May 28, 2009, 09:28:37 »

My tomato plants are rapidly outgrowing my mini greenhouse, have planted 4 of them outside, but a couple of these are starting to go yellow round the edges of the bottom leaves, which I assume is blight (they have been well fed)

The others in the greenhouse look healthier, but they do get frazzled on a hot day. Was going to try to make a large polythene bender to put them in, but am wondering how tightly it needs to be sealed to keep the blight out, whether it is better to leave lots of ventilation so it doesnt get too hot and humid?

saddad · « **Reply #1 on:** May 28, 2009, 09:36:12 »

As long as there is a cover to stop direct rain fall it doesn't need to be too "sealed"... that would just encourage grey mould... It's quite normal for the lower leaves to start to go yellow... :)

raisedbedted · « **Reply #2 on:** May 28, 2009, 09:48:34 »

I grow mine in a tunnel which is completely open at the ends. Doesn't get too hot so I don't have to water every day and did not get any blight last year. In fact the crop was better than my plot neighbours who has a fully enclosed polytunnel.

thifasmom · « **Reply #3 on:** May 28, 2009, 09:51:49 »

here is a quick suggestion, why not throw an old net curtain/ a double layer of fleece over the top of the mini greenhouse to create a bit of shade, this should help stop the frazzling of plants :).

kenkew · « **Reply #4 on:** May 28, 2009, 10:45:16 »

Lewic: High tall are your plants now? Got any pic's?
Remove all the yellow leaves and outside tom's need to be kept away from your spuds. The yellowing could be a magnesium deficiency. Sprinkle a bit of Epsom salts around the base and water it in.

lewic · « **Reply #5 on:** May 28, 2009, 11:26:18 »

Fleece is a good idea - will do this later, thanks.

Havent got any pics yet, but the biggest plant is about 18" high and most are about 10". The outside ones are planted in between onions, in a raised bed about 2 foot away from spuds..

Robert_Brenchley · « **Reply #6 on:** May 28, 2009, 12:23:37 »

Keeping them away from spuds isn't going to make any difference on an allotment! Once the disease appears, it soon spreads to everything.

kenkew · « **Reply #7 on:** May 28, 2009, 16:05:32 »

That's scare-mongering, Robert.
To say that is to state that every allotment will be blighted by a single infection. Not so.
Even where allotments back on to each other, it's not a certainty that they will all be infected. (Quite likely if close to each other, but not a certainty.)

Tee Gee · « **Reply #8 on:** May 28, 2009, 16:44:03 »

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whether it is better to leave lots of ventilation so it doesnt get too hot and humid?

Yes every time!

A well ventilated place keeps the plants dryer and the air less humid.

From what I can see in a number of cases is the 'watering' is most likely the problem.( and the same applies to potatoes...I never water potatoes!)

In my opinion damping down is a bit of nonsense it lifts the humidity and creates the ideal condition for blight!

Look it this way;

Blight is spread by spores! the spores are a dry! so if the land on a dry leaf they are just as likely to be blown off again.

Whereas if the leaf is wet/damp the spores will stick to the leaves............this can be then be the start of your problems.

I rarely if ever water/spray water over my plants! I prefer to water into pots at the base of the plant, and just let it overflow a little to wet the upper roots.

This keeps the humidity down, the plants get all the water they need plus I haven't watered the weeds forming around the plants so this method keeps these under control as well.

This is a typical layout for my tomatoes;

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but a couple of these are starting to go yellow round the edges of the bottom leaves, which I assume is blight (they have been well fed)

This does not necessarily mean you have blight, your plants may need magnesium as has been said already.

The leaves might be lacking light!

They might be the original leaves that haven't taken kindly to the move from propagation to growing on!

They might be over fed!

What are you feeding with? and are their tomatoes on your plants.

The roots may be saturated what with all this watering and feeding.

Finally I don't think your plants are necessarily blighted..... my vote is the move from indoors to outdoors is the more likely cause of the problem.

Remove the affected leaves then wait a week or two to see if the now green bottom leaves turn yellow!

If they do then yes you have a problem!

littlebabybird · « **Reply #9 on:** May 28, 2009, 17:01:50 »

one more thing to add to that list, did you harden them off before you put them outside?
lbb

Robert_Brenchley · « **Reply #10 on:** May 28, 2009, 19:13:25 »

Quote from: kenkew on May 28, 2009, 16:05:32

That's scare-mongering, Robert.
To say that is to state that every allotment will be blighted by a single infection. Not so.
Even where allotments back on to each other, it's not a certainty that they will all be infected. (Quite likely if close to each other, but not a certainty.)

I was thinking in terms of a single plot. If you get it at one end, you'd be extremely lucky not to get it at the other.

kingston boy · « **Reply #11 on:** May 28, 2009, 20:52:28 »

A lot of all your answers are good but why dont you all look at Blightwatch.co.uk.
It explains what and how and when to expect the dreaded blight. Type in your postcode, join and they let you know when its coming.

lewic · « **Reply #12 on:** May 28, 2009, 21:05:15 »

TeeGee your setup looks great. One day maybe I will have the time, money and/or skills to do something similar!

Am feeding with Miracle Gro organic plant food. No clue what is in it but it smells good enough to eat!

Both plants went straight in the ground a couple of weeks ago (forgot the hardening off bit..) and they did sulk for a couple of days but perked up again quickly.

They dont look in a really bad way, but both my neihbours lost the lot last year.

thanks

Cath[attachment=1][attachment=2]

amphibian · « **Reply #13 on:** May 28, 2009, 23:18:20 »

Doesn't look like blight to me. Maybe just nutrient deficiency from their pot stage, or scorch. If upper leaves look okay I wouldn't worry. Easier said than done, I worry about every discoloration I encounter, but most the time the plants battle on despite my anxieties.

Tee Gee · « **Reply #14 on:** May 29, 2009, 17:07:12 »

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Am feeding with Miracle Gro organic plant food. No clue what is in it but it smells good enough to eat!

Both plants went straight in the ground a couple of weeks ago (forgot the hardening off bit..) and they did sulk for a couple of days but perked up again quickly.

Well for starters I guess you are OVER feeding which can be as bad as UNDER feeding.

I never feed from planting out till the 'set stage' (see picture) there should be enough fertilser in your compost to get you to this stage without having to feed again.

From what I can see the feed you are using a high Nitrogen fertilser (7-1-2) and it is very high at that and if you are, as I suspect, over using it! then this might be the root of your problem, root being the operative word, they may be getting burned/scorched!

I would leave off this particular fertilser and start using a high POTASH fertiliser at the 'set stage' (see picture).

If you prefer to use Miracale-gro products then use this; http://www.scotts.com/smg/catalog/productTemplate.jsp?proId=prod70358&itemId=cat70048&tabs=general when your plants reach this stage;

BTW any Tomato fertilser will do from this stage so go for the most ecconomical, they all do the same thing!

kenkew · « **Reply #15 on:** May 29, 2009, 21:56:40 »

And unless you want to expand sideways, dont forget to remove this one.

[attachment=1]

Eristic · « **Reply #16 on:** May 30, 2009, 00:53:34 »

Well I'm with Robert on this one. Blight on tomatoes does spread like wildfire, sometimes even faster. I've got my kevlar body suit on and I'm ready for the sharp knives but I postulate that the epidemics of blight that has infected the tomatoes for the past 3 years does not, That's NOT, come from the potatoes. Not directly anyway.

For anyone who has not experienced blight of tomatos, the rate of spread is staggering. In fact if you only visit the plot once a week you could walk away proud of your developing crop only to come back a week later to a black pile of sludge on the ground.

Last year I could not find any infected potatoes on the site at all and some of my tomatoes were grown adjacent to my Desiree spuds which remained clean.

Digeroo · « **Reply #17 on:** May 30, 2009, 20:04:13 »

I must say I like the little pots beside each tomato plant Tee Gee Presume it is much easier to keep the water off the stems and leaves. How deep are the pots. I have plenty of emply yoghurt pots do you think they would do the job. I have also seen this done with the tops of plastic milk bottles.

Tee Gee · « **Reply #18 on:** May 31, 2009, 19:03:24 »

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How deep are the pots.

In this case they are cream cartons and are about 4"-5" deep.

I have used 5" plant pots before today.

If they are too small I find that to get enough water to each plant you would have to let them overflow.

I would say anything around one litre capacity is best!

lewic · « **Reply #19 on:** May 31, 2009, 19:58:32 »

Checked my plant food info and it is 3-2-6.
http://www.lovethegarden.com/products/plantfeed/miracle-gro-organic-veg-liquid.html
Didnt realise there was a techy formula for these things!

Have started making a shelter for the toms, its rather wonky at the mo as I ran out of canes to support it.

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Author Topic: Tomato blight protection? (Read 9334 times)

amphibian