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 a Haworthia attenuata to maturity
Flower a Lithops optica 'Rubra'
Flower a Sedum morganianum
Flower a Senecio serpens
Grow a Lithops optica 'Rubra' to maturity
Flower a Fenestraria aurantiaca
Flower a Haworthia attenuata
Flower a Echeveria runyonii
Flower a Senecio rowleyanus
Flower a Kalanchoe thrysiflora
Flower a Cheiridopsis denticulata
Flower a Pachyphytum oviferum
Flower a Kalanchoe rotundifolia
Flower a Echeveria 'Lola'
Flower a Sedum pachyphyllum
Throw one hundred mature plants into the garden
Grow an Agave macroacantha to maturity
Grow an Echeveria runyonii to maturity
Grow a Fenestraria aurantiaca to maturity
Grow a Sedum morganianum to maturity
Grow a Kalanchoe thrysiflora to maturity
Grow a Cheiridopsis denticulata to maturity
Grow a Senecio serpens to maturity
Grow a Senecio rowleyanus to maturity
Grow a Pachyphytum oviferum to maturity
Flower a Aloe 'Blue Elf'
Flower a Pachyphytum fittkaui
Flower a Echeveria glauca
Flower a Aloe vera
Flower a Sempervivum
Flower a Pachyphytum glutinicaule
Flower a Pachyphytum hookeri
Throw fifty mature plants into the garden
Grow an Agave 'Blue Glow' to maturity
Grow a Sedum pachyphyllum to maturity
Grow an Echeveria 'Lola' to maturity
Grow a Kalanchoe rotundifolia to maturity
Throw ten mature plants into the garden
Throw one mature plant into the garden
Grow an Aloe vera to maturity
Grow an Aeonium to maturity
Grow an Aloe 'Blue Elf' to maturity
Grow an Echeveria glauca to maturity
Grow a Sempervivum to maturity
Grow a Pachyphytum glutinicaule to maturity
Grow a Pachyphytum hookeri to maturity
Grow a Pachyphytum fittkaui to maturity