This article quoted from royal queen seeds make me think twice about my auto medium (FFOF) :
SOIL AND AUTOFLOWERING STRAINS.
Autoflowering strains prefer light, airy soil with a relatively low level of nutrients. This makes standard shop bought potting soil less ideal than a specialty ‘lighter’ mixes. This isn’t to say you cannot use normal soil, but you will get much better results if you tailor it to your cannabis. One option is to make your own soil. A basic recipe that does well with autoflowering strains is as follows:
- 3 parts peat moss
- 3 parts compost
- 2 parts perlite, pre-wet
NUTRITION AND AUTOFLOWERING STRAINS
Making sure your autoflowering cannabis strains have enough nutrients is a fairly straight forward process, but it is worth remembering that they do not require nearly as much as conventional photo-period strains, so whatever you give them, do it VERY lightly.
To begin with, your seedlings will need nothing but water for their first 2 weeks. Starting week 3 you can start adding vegetative nutrients, but do so sparingly. (1/8-1/4 strength of recommended dosage).
Once your plants have shown signs of flowering for at least a week (this will vary from strain to strain, and plant to plant) switch over to a bloom nutrient. This is done a week into the flowering process because autos will often continue to “flesh out” for about a week into the flowering process and still require vegetative nutrients. Again, start out very sparingly. (1/8-1/4 strength of recommended dosage). Supporting this continued growth tends to result in better overall yields.
Once again, bear in mind that auto-flowering cannabis strains do not need nearly the same level of nutrition as their photo-period counter parts, so go very easy to begin with until you get a better feel for their requirement. As with all varieties of cannabis, the actual needs can vary quite a bit strain to strain, so investigate your certain strain, and don’t be afraid to adjust your feed if your gut is telling you to.
