Phosphorus

[copper2]

I have a phosphorus problem I think(underside of tomato leaves are purple) and I added bonemeal but that doesn't seem to be helping. Can PH or too much of another nutrient be stopping intake?

 

[Chris09]

There are a few things that could purple color on the underside of tomato leaves.
What are the night time temps there, are the tomato leaves curled?

Bone meal is a slow release fertilizer and it will take sometime for the phosphorus to break down into soil and absorbed into the plants.
Bone meal will add both phosphorus and calcium to the soil but if your showing signs of phosphorus decency it isn't really going to help anytime soon. A much better option is a good liquid fertilizer like Fox Farm Neptune's Grow Big or Harvest Organic Fish/Seaweed Blend Fertilizer if you want to go organic. If your ok using a conventional fertilizer try using Miracle-Gro Tomato Plant Food or Jacks Fertilizer (20-20-20).

 

[copper2]

The nights have been warm here except for one of two nights but the tomatoes were showing purple before those couple of cooler nights. I'll have to check if the leaves are curled but if they are what causes it?

 

[Chris09]

The nights have been warm here except for one of two nights but the tomatoes were showing purple before those couple of cooler nights. I'll have to check if the leaves are curled but if they are what causes it?

Leaf curling is another sign of phosphorus decency but it means that there in a "different stage" of phosphorus decency.
If it was me I would decently hit them with a liquid fertilizer.

 

[copper2]

Okay, thanks!

 

[lazy gardener]

Any time I see potted plants, including seedlings looking a bit off color, I give them some epsom salts in addition to the liquid fertilizer. (You can mix it right in with the miracle grow) (1 Tbsp ES/gal H2O) I can almost watch those leaves green up after a dose of epsom salt!