Why are my Cauliflower Leaves Turning Yellow

[WB2ORJ]

I got several cauliflower, Brussel sprouts and broccoli plants from a local very reliable nursery. I prepared my beds by tilling, adding some compost and some horticultural sand in recommended proportions. The beds are on a bit of a grade and I planted the cauliflower in top 2 rows, then Brussels then Broccoli. These were first planted as 4-6" high plants about 4 weeks ago (I'm in lower NY state) during a mild week to harden them outdoors but since then we have have several cold nights down to 40F and many very wet days. The Brussels and Broccoli are doing great but the cauliflower has leaves turning yellow. At first I thought these were the older leaves from some shock but I now see even some new leaves turning. I have not watered during the past 2 weeks due to periods of heavy rain and my testing of the soil shows its quite moist. Is this some cauliflower specific bug, how do I treat?

Thanks in advance.

 

[headfullofbees]

It's no bug.
Cauliflowers are the most difficult of brassicas to grow well; almost petulant princesses.
I;ve even been known to call them "Millenial Brassicas,"
They can be awkward to transplant, & if they've not been well looked after previously you WILL have trouble.
To remedy the chlorosis of the leaves, I'd be inclined first to try a handful of horticultural epsom salts in a gallon of water, watered into the ground to help nutrient uptake, and a fast nitrogen source, like 9 water - 1 urine.
The horticultural sand was actually unnecessary for brassicas; they have their own rules; their own likes & dislikes etc.

 

[WB2ORJ]

Thanks, OK did what you recommended Saturday, then we had a nice rain yesterday. How long before I should see improvement? I guess the older yellow leaves wont improve so I would just watch the new growth?

 

[headfullofbees]

Remove the yellow leaves; they are of no further use.
Walk around the rows firming your caulis in.