What's this on my tomato leaves?

[SimpleSimon]

I've got 8 plum roma looking very healthy and laden with fat fruit but a few of them are developing these spots on the leaves. Any ideas?

[quanglewangle]

Scorching, maybe. Has it been very sunny where you are?

[SimpleSimon]

It was but these leaves are quite shaded. The GH these are in is packed. They are mostly at the bottom. A few about mid height.

[Jungle Jane]

Its an old leaf,sometimes when the plant needs food it’ll take it from lower leaves so the new growth has enough nutrient. Have you fed them at all please let us know,sometimes over fertilising can cause problems too.

[goosander]

Was going to ask myself but was unable to take photos as my problem seams the same.
Every year i intend cutting down on the number of plants and still have to throw out some.
Thanks for your help,
Bob.

[SimpleSimon]

Its an old leaf,sometimes when the plant needs food it’ll take it from lower leaves so the new growth has enough nutrient. Have you fed them at all please let us know,sometimes over fertilising can cause problems too.

It's certainly not underfeeding as they on a self watering system (a rain gutter wicking one tho with ducting not guttering) that has a constant supply of nutrients. The plants are huge considering they are bush tomatoes. Nearly head height. It's possibly over feeding I guess. I use the elixir gardens tomato feed that's 1g / litre but put about 100g in the full waterbutt that's 120litres. That lasts the 8 plants about 2 or 3 weeks depending on the temps.

Guess just checking it's not the start of something terminal as the crop from these 8 plants looks likes it going to be enormous so don't want to loose them.

[Jungle Jane]

It looks like a magnesium deficiency,Epsom salts can help correct it if it was really bad but this isn’t in the new growth so it should be ok it being an old used leaf. Sometimes if a plant gets too much of one nutrient it can affect the uptake of other nutrients.

[Snoop Puss]

Interesting. I don't feed constantly, just a bit and then a week or so's break. I don't know that particular product, but would be interested to hear what other people's feeding regimes are.

[Bren In Pots]

Snoop my toms are planted in the GH border feeding them once a week when fruits have set with commercial tom feed one week then comfrey the next.

[burnie]

Mine are getting fed twice a week with seaweed feed, but at half strength mix, been doing this for a few years now and seems to work, I have seen this type of leaf problem, but I remove the old leaves as soon as I see this, doesn't seem to cause any problem, I get a good crop.

[Mr Bones]

Re feed - ours in bags and buckets had a handful of BFB at time of planting and get a litre of home made liquid seaweed feed in 5 litres of water twice a week.
Those in the ground had a handful of BFB at time of planting out and aren't fed again.

[SimpleSimon]

The constant feeding regime is based on the way the quad grow works. I was using their nutrigrow plant food which is a soluble hydroponic feed you provide in the reservoir constantly. This ducting system is just a DIY version of the quadgrow (each 8 plant run costs £22 to build excluding the water butt). I've too many plants on these wicking systems to use nutrigrow in terms of price. The exlir gardens stuff is similar in terms npk and trace elements but without the calcium (nutrigrow is 2 part). And just way cheaper.

The plants are deep green and absolutely massive so it must be working. I do wonder if perhaps on the last fill of the butt i spannered the measurements and some plants have a few leaves like above. They are pretty rare tho so just gonna chop them off.

Out of interest does anyone ever prune bush toms? Or get rid of leaves to ripen the fruit once all the flowers have set. These must have just about the reached their max height so I presume the top trusses will be their final. They are just setting fruit now. But it's a full on jungle. Most of the fruit isn't going to be getting much light to ripen.

[Jungle Jane]

The top trusses might not be the final truss with a bush tomato,they can send out a side shoot from lower down & have flowers on,they’ll keep going throughout summer,careful what you do prune off but I always remove the lowest leaves under the lowest truss of fruit so leaves aren’t close to the soil.