What Is A DIF?

A warmer day than night gives a positive DIF and generally encourages more stem elongation in responsive plants.

A smaller or negative DIF tends to suppress elongation.

UMass notes strong responses in several plants you’re growing, including chrysanthemum, salvia, geranium and rose.There’s an easier version that interests me for your greenhouse: the cool-morning pulse.Then measure:height | internode length | branching | days to saleable size

Don’t immediately apply this greenhouse-wide. Different species and cultivars respond differently, and average daily temperature still affects development rate.

But it is exactly the sort of small controlled experiment your greenhouse is perfect for.

We should eventually give your command system an Experiment Log: Question → treatment → control → measurement → result → production rule That way your greenhouse gradually stops depending on generic advice and starts building its own operating manual. 

Batch B: cool-morning treatment during rapid vegetative growth.

We should eventually give your command system an Experiment Log: