Young tomato plant deficiencies - yellow leaves!

[colonel]

Hello there,

A question about young tomato plants.

I recently pricked out and potted on my young tomato plants, they range from about 4 inches to 6 or 7 inches and some have yellowish leaves! The yellowing is in between the veins. Does anyone know the cause and solution for this?

Some also have a slight whitening of tnhe leaves. I am not sure whether this is becuase they have been in strong sunlight for a few days or another reason. Any advice re this and general tomato seedling/ you plant care would be much appreciated.

Also a lot of them have purple - ish stems. Is this another deficiency or problem that I need to make adjustments in order to rectify.

Any advice re tomato plants and their care would be most welcome.

Thanks, stay safe and enjoy the bank holiday weekend.

Happy growing

[ecudc]

The whitening is almost certain sunlight that is a bit too strong. Make sure you are watering from the base so you don’t get water droplets on the leaves that can magnify it and if you are able to provide some shading on the strongest days.

Purple tinges are usually caused by it being a bit cold for the tomatoes liking. Usually they will recover just fine but growth will be slightly retarded until they warm up.

Chlorosis (yellowing) is usually caused by a nutrient deficiency. It might be time to pot on or feed with a general tomato feed. Magnesium deficiency if usually the only one that you would treat specifically in potted tomatoes but the yellowing would be the other way around in that so just a general feed should be enough.

[nickdub]

Most of the symptoms you describe are almost certainly down to the plants getting very cold overnight - they really don't like it if the temp drops below 10 C for more than an hour or so. The yellowing could be magnesium deficiency but that would be unusual early in the season as there is generally plenty of nutrients in new potting compost for young plants.

[MarkPelican]

As Nick says above, most of the symptoms you have described can be attributed to being in strong sunlight and being too cold.

I would guess from what you are describing that you have your plants in an unheated greenhouse. This can mean that they are in strong sunlight during the day and in the cold at night. Half of my tomatoes are still being "mollycoddled" with the daily trip in and out. The others (which I probably won't grow through to maturity) are left in the unheated greenhouse and show many of the symptoms you have described.

The only proviso is cultivar. In the past I've found that yellow fruited varieties tend to have paler leaves than other colours and this year, I'm growing Dancing with Smurfs and Blue Ambrosia for the first time and the plants are a lot bluer than any of the other cultivars.

Finally, I've found that the leaves of potato leafed varieties are more likely to get sunburnt than regular leafed varieties.

[Mark_Riga]

If they are too cold at night in a greenhouse, covering at bedtime with a double layer of horticultural fleece will help if they are on the floor, not so much if on staging.