Free guides · Late winter
Seed Starting Cheat Sheet
How we start cut flowers indoors, with sowing depth, temperature and light for each of the seeds we save.
The setup
- Fresh seed-starting mix, not garden soil, in clean cell trays with drainage.
- Warmth: most flowers sprout fastest at about 70–75°F. A heat mat helps.
- Light: a windowsill isn't enough. Hang grow lights a few inches above the seedlings for 14–16 hours a day, and raise them as the plants grow.
- Water from below: set trays in water for a few minutes so the mix stays moist but never soggy.
- Airflow: a small fan on low helps prevent damping off and makes stems sturdier.
Our seeds at a glance
| Seed | Sowing | Sprouts in | Notes |
|---|---|---|---|
| Snapdragon | Press onto the surface. Needs light. | About 1–2 weeks | Likes cooler temperatures once it's up |
| Strawflower | Press onto the surface. Needs light. | About 1–2 weeks | Don't let it dry out while sprouting |
| Zinnia | Cover about ¼ inch | Often under a week | Fast and forgiving |
| Celosia | Cover very lightly | About 1–2 weeks | Wants warmth; cold stalls it |
| Amaranthus | Cover very lightly | About 1–2 weeks | Grows big. Give it room. |
| Dahlia | Cover about ¼ inch | About 1–2 weeks | Every seedling is a brand-new variety |
From tray to garden
- Once seedlings have their first true leaves, thin to one per cell.
- Pot up anything that outgrows its cell before planting time.
- Harden off for 7–10 days: a few hours outside in shade at first, building up to full sun and overnight.
- Plant out on a calm, cloudy day if you can, and water well.
All of our seed is open-pollinated, so you can save your own next fall.
From Knollwood Flowers · Moultonborough, NH · knollwoodflowers.com
