Q: Saw your article last week about seed starting supplies. How do I know what seeds to plant when? —G. S. Westhampton
A: Your seed packet should indicate how many weeks before the last frost date you should start your seeds indoors or outside. When is our average last frost date here in the Pioneer Valley? According to the National Climate Data Center, the average last frost date here in western Massachusetts is around May 15. If you want extra assurance your transplants will not get zapped by a last minute visit from Jack Frost, push your target date out a week or two, to May 22 or May 29.
Cool weather vegetables such as lettuce, onion, cabbage, broccoli, and radishes should be planted earlier than warm weather vegetables such as tomatoes, beans, and peppers. The cool weather ones will even tolerate a light frost, but do have a sheet or other cover handy to cover them for the surprise heavy frost day or night until mid-May. Last year we had sleet and freezing rain on April 15 — remember that?
Our Western Massachusetts Master Gardener’s website has gardening-related articles you might find helpful related to seed starting at wmmga.org.
If you are working with native seeds, ideally plant them outdoors in the Fall around the first frost as they are designed to germinate after they have gone through their species-specific dormancy period. Humans are not the only living entities that grow best when fully rested!
If you missed that opportunity and would like to germinate native seeds now instead, simply plant your native seeds in flats and put them outside. If you do this in the next week or so there should be enough cold weather and snow left for the seeds to break dormancy and germinate in time for planting.
For example, if you have native milkweed, goldenrod or columbine seeds — all great for pollinators, by the way — you can plant them in plastic flats and put them out by the compost pile if you have one, or another somewhat protected area. They will get snowed on, will freeze and thaw, and then you can plant whatever has germinated in the spring.
Another very helpful resource covering seed starting and what to plant when is a book by our very own Master Gardener pioneer Ron Kujawski and his daughter Jennifer Kujawski entitled “Week-by-Week Vegetable Gardener’s Handbook.” Ron started the Western Massachusetts Master Gardeners Association back in the mid-1980s.
Good question, G.S. Thanks for asking a (local) Master Gardener.
Have a gardening dilemma? Please send questions, along with your name/initials and community, to the Western Massachusetts Master Gardener Association at AskAMasterGardener@wmmga.org. One question will be selected and answered per week.
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