Start your plants off the right and most effective way, with Jiffy Windowsill Greenhouses. Jiffy's series of lightweight, plastic planting trays with various small pop-out cells and humidity domes are perfect for growing vegetables and flowers. Prepare Strips: Fill peat pots in the base tray with your sowing medium (not included). We suggest using Premium Seed Starting Jiffy-Mix. Water thoroughly - enough to saturate walls of strips. Add Seeds (seeds are not included). Sow your seeds according to the instructions on your seed packet. Germination - Once seeds have germinated, prop the dome lid open. When seedlings grow true leaves remove the lid completely and place them in a sunny location.