Here is the full list of all 47 Viridi achievements. It takes around 15-20 hours to unlock all of the achievements on Windows.
Grow an Echeveria 'Lola' to maturity
Grow a Senecio serpens to maturity
Grow an Echeveria glauca to maturity
Flower a Haworthia attenuata
Grow a Haworthia attenuata to maturity
Flower a Lithops optica 'Rubra'
Grow an Agave 'Blue Glow' to maturity
Grow a Lithops optica 'Rubra' to maturity
Flower a Cheiridopsis denticulata
Grow an Aeonium to maturity
Flower a Echeveria runyonii
Flower a Kalanchoe thrysiflora
Grow a Cheiridopsis denticulata to maturity
Flower a Pachyphytum fittkaui
Flower a Kalanchoe rotundifolia
Grow an Echeveria runyonii to maturity
Flower a Pachyphytum glutinicaule
Grow a Kalanchoe rotundifolia to maturity
Flower a Aloe vera
Grow a Pachyphytum fittkaui to maturity
Flower a Sempervivum
Flower a Aloe 'Blue Elf'
Grow an Aloe vera to maturity
Flower a Pachyphytum oviferum
Flower a Pachyphytum hookeri
Grow a Kalanchoe thrysiflora to maturity
Grow a Sempervivum to maturity
Grow an Aloe 'Blue Elf' to maturity
Grow a Pachyphytum hookeri to maturity
Grow a Pachyphytum glutinicaule to maturity
Grow a Pachyphytum oviferum to maturity
Grow a Sedum pachyphyllum to maturity
Grow an Agave macroacantha to maturity
Grow a Fenestraria aurantiaca to maturity
Grow a Sedum morganianum to maturity
Grow a Senecio rowleyanus to maturity
Flower a Echeveria glauca
Flower a Echeveria 'Lola'
Flower a Sedum pachyphyllum
Flower a Senecio serpens
Flower a Fenestraria aurantiaca
Flower a Sedum morganianum
Flower a Senecio rowleyanus
Throw one mature plant into the garden
Throw ten mature plants into the garden
Throw fifty mature plants into the garden
Throw one hundred mature plants into the garden