young cauliflower plant - yellow splotches on leaves

[alexen]

Hi everyone

This is a picture of my young cauliflower plant which I grew from seed.

I am starting it indoors under a grow-light and it is growing in freshly bought potting soil.

I actually have three of them and the leaves look the same on all of them. I am trying to understand what could be causing the yellow splotches.

Any ideas?

Thanks for your help!

 

[Chuck]

They are chlorotic, either nitrogen or iron or both. Have you ever fed them any fertilizer and if so with what and when?

 

[alexen]

I have not fertilized them yet. They are only abut a month old and I thought the soil itself would have enough nutrients to sustain them. I guess not!

How soon do you start fertilizing seedlings?

I have some kelp powder on hand. Would that be good? Any suggestion for amount to use in a small 4" starter cup like this?

 

[Chuck]

Kelp meal is mainly used for adding micro-nutrients. Its NPK is 1-0-4 and does not have enough NPK for sustained plant growth. It is a great additive to fertilizers which have low amounts of micro-nutrients. Your plant is suffering from interveinal chlorosis. This can be from a lack of nitrogen or some micro-nutrient such as iron or manganese. Potting soil normally does not have much or any NPK in it so when a plant reaches its first true leaf stage it starts needing nutrients. The reason the plant has grown like it has is because the seed itself has enough nutrients in it to sustain the plant through the cotyledon stage but once the true leaves start to appear all of the nutrients have been used up. Get some good liquid fertilizer such as HastaGrow and use as per directions which I think is 1 oz per gallon of water. You can add 3-4 tablespoon of the the kelp to the fertilizer if you like or just spread it around the base of the plants and when you water or fertilize the plant the kelp will go into solution. You may as well fertilize whenever you water which is probably about once per week.

 

[alexen]

Thanks for the great info, Chuck. Very helpful! I will order some of the HastaGrow.

I forgot to mention that I have some Masterblend which I use with the three part mix for some of the plants I am growing in hydroponic systems (1) MasterBlend 4-18-38; 2) calcium nitrate 15.5-0-0; 3) epsom salt).

Would I be able to use this masterblend solution to fertilize my plants until the HastaGrow arrives?

 

[Chuck]

Thanks for the great info, Chuck. Very helpful! I will order some of the HastaGrow.

I forgot to mention that I have some Masterblend which I use with the three part mix for some of the plants I am growing in hydroponic systems (1) MasterBlend 4-18-38; 2) calcium nitrate 15.5-0-0; 3) epsom salt).

Would I be able to use this masterblend solution to fertilize my plants until the HastaGrow arrives?

This product is not something I recommend but it will work short term.. This is a synthetic fertilizer and very low in nitrogen which probably is the cause of your problems. This product is much better suited for more mature plants than seedlings.