Categories: All Equipment Consulting Greenhouses Built Onsite DIY Greenhouse Kits All / 12' x 12' DIY Passive Solar Greenhouse Kit $7,400.00 12' x 18' Passive Solar Greenhouse Kit $8,200.00 12" x 24" Passive Solar Greenhouse Kit $10,700.00 12" x30' Passive Solar Greenhouse Kit $12,700.00 12' x 36' Passive Solar Greenhouse Kit $16,600.00