SWEET PEA STARTING INSTRUCTIONS
INCLUDING VERNALIZATION
USE AN IMPORTANT TECHNIQUE OF JAPANESE CUT FLOWER CULTIVATION:
VERNALIZE YOUR SPROUTED SWEET PEAS FOR HIGHER QUALITY CUTS
starting your sweet peas:
1. Soaking (optional, but a Quick soak allows for more uniform germination, with minimal risk of fungal issues).
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Place seeds in a clean container of room-temperature water.
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Soak for 2 hours. sET a TIMER!
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Drain and discard the water.
2. Initial Germination at Room Temperature
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Spread soaked seeds on a moist paper towel in a freezer bag or glass jar at room temperature (18–22 °C). Ensure clean WATER, PAPER towels, AND FREEZER bags to DETER FUNGAL ISSUES.
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seeds will germinate over several days. If mold APPEARS, USE A CLEAN PAPER TOWEL WITH LESS MOISTURE.
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Monitor carefully: seeds are ready for the next step when the radicle (taproot) just begins to emerge.
3. Handling Slow or Hard Seeds
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After 48 hours, check for ungerminated seeds.
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If seeds remain hard/ haven't swollen with moisture, carefully nick the seed coat in one spot with a clean nail clipper.
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Take care to cut only the seed coat, not the embryo inside.
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Once seeds swell and show radicle emergence, add them to the refrigerated vermiculite tray (sEE NEXT STEP).
4. Transfer to Vermiculite and Refrigeration (or SOW in cells and skip to step)
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Place germinating seeds on top of moist (not wet) vermiculite in a clean tray or clamshell.
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Move the tray into an unsealed freezer bag (to allow air exchange while maintaining humidity).
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Place in the refrigerator (ideal temp 2°C).​
5. Cold Treatment (Vernalization) - Optional but Beneficial!
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Keep the tray in the refrigerator (dark, cool, moist conditions) for 30–40 days for spring/summer-flowering varieties. all of the japanese varieties we offer are spring/suMMER fLOWERING.
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Vernalization delays flowering slightly but promotes longer stems and higher cut-flower quality.
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While not strictly necessary, many growers find it worthwhile, AND, ALONG WITH CORDONING, THIS IS AN IMPORTANT CULTURAL METHOD USED BY JAPANESE GROWERS TO PRODUCE TOP-QUALITY CUT SWEET PEAS.
left: radicle (root tip) HAS EMERGED. SEEDS MAY TAKE SEVERAL DAYS AT ROOM TEMPERATURE TO ACHIEVE THIS STAGE. cONTINUE CHECKING EACH DAY, AND SOW SPROUTED SEEDS AS BELOW. fOR SEEDS THAT HAVEN'T GERMINATED AFTER 72 HOURS, CAREFULLY NICK THE SEED COAT, AND ALLOW A FEW MORE DAYS FOR GERMINATION.
right: sPROUTED SEEDS ARE SOWN IN TRAYS ON VERMICULITE, ENCLOSED IN AN UNSEALED FREEZER BAG. tRAYS ARE HELD DARK AND COOLED TO APPROXIMATELY 2c IN A fRIDGE OR COOLER FOR 30-40 DAYS (SPRING/sUMMER-FLOWERING VARIETIES). tHIS ENCOURAGES UNIFORM FLOWERING ON HIGHER QUALITY, LONGER FLOWERING STEMS.
