I like the addition of the countdown for sure, but one request: the option to use it - can it be a check box on the home page next to each Status box? this makes seeing what is going on much easier (for instance, I like the countdown for flowering, but not for the veg mostly, so I have to flip flop to the last tab to uncheck for all/nothing). I also like the Patient tab and would suggest adding a freetext box for notes, maybe a dropdown for symptoms (eg:Glaucoma, Pain Management, Muscle Spasms, IBS, Appetite Management, MS, PTSD, etc), strains that help (eg: user prefers Indica or Sativa. or link plants to patients) --- this type of long term data can be useful to the community at large as well, as it can help show trends and prove what types of medication work best for certain conditions.
not trying to second guess you .... but why not just link the countdown timer to the existing "Flower Time (Advertised): X" and have it trigger when user does "Phase Change to: Flowering"? this eliminates a couple user steps and conserves that space.