I'm a bit busy (again) this week (but who doesn't?). Nothing special is done to my system during the weekend as I was away to pick up my kids at my mom's place. My mom gave me a bunch of mint to be planted and so I divided it into a few cuttings and one cutting goes into the grow bed. The others I planted in my special strawberry planter which I didn't use to plant strawberry.
Anyway the reason for this post is to share what I found on the internet. I've been googling about nutrient for plants as my pak choi has difficulty to get green leaf, despite healthy. Look what I found from a company that supplies fertilizers in the US (NACHURS): about NITROGEN
"Nitrogen serves as the source for the dark green color in the leaves of various crops. This is a result of a high concentration of chlorophyll. Nitrogen combined with high concentrations of chlorophyll utilizes the sunlight as an energy source to carry out essential plant functions including nutrient uptake."
There you have it. Looks like my system is still not mature enough as the plants show difficulty to get greener leaf.
"Nitrogen deficiency shows up in the yellowing or chlorosis of the plant leaves. The yellowing will start in the oldest leaves, and then will proceed to develop on younger leaves if the deficiency continues."
My system don't have the above problem, so the level of insufficiency of nitrogen could be low. A good guide for those into gardening and have no idea what is going on in their plants: Micronutrient Deficiencies
And the role of micronutrients.
Hope this'll help.