My soil is pH'd when i get it out of the bag, the soil brands are starting to have to display the nute level and pH as well as the percentage of peat on the back of most bags where we live. The soil was tested a year or so ago and held up to the manufacturers claims, just over 6.5 out of the bag. I have only added tap water which again is not the problem. I have heard some say that we need a dedicated thread and test on commercial soil so we can work out what the contents, nutes etc etc are.
The the real problem with my soil seems to be that it is low in nutes, i use to get bigger plants per volume of soil but steadily they got smaller and smaller and seemed soil has less nutes in. Now even my seedling soil isn't suitable and seems almost nutrient devoid, i am having to fertilize seedlings that i have never had to and am mixing in a lot of the flowering compost as well which i would never do due to it burning seedlings. This is very obvious in my grow as as soon as i give weak nutrients the seedlings take of and grow faster than i have ever seen before. The plant in the picture is no bigger than it looks, i just missed getting the top of the plant in, but it has had a week and a half of good growth and recovery so you can see that the plant was very small when it had its nutrient problems. Basically i am down to fertilizing as soon as the first true leaves have formed and the second are just getting going. The roots haven't even filled the pot.
I am very concerned about this and have a similar thread for my flowering plants where i repot into the flowering compost which use to have strong nutes for 4/5 weeks and even before it has roots poking out the bottom of the pot it wants ferts, its like the soil isn't strong enough in the first place!!!
I am sorry if it is a long post but as you can see a real problem none the less! I am wondering if it is just low in one particular nute or a couple stopping the rest from being absorbed and the plant growth stunted. Wish we had some soil reps on here to tell the truth about our soil. It just dosen't feel or look like nitrogen (gut feeling) and was thinking, looking at the plant, potassium/phosphorous and calcium. This is a bit of a far out and radical conclusion considering its in veg and nitrogen is the big one here. I have seen a drawing and pic of leaves like this in the 'Marijuana horticulture the indoor/outdoor growers bible', think it was potassium and calcium but i gave that book away because thought i knew it all and it didn't help diagnose the deficiencies! Thanks