by Julia Frisbie
posted 2-22-22
If you’re like me, at this time of year you’ve amassed an embarrassingly huge collection of seeds and are wondering where you’ll cram them all, and how you’ll get them off to a good start. Or maybe you picked up a few seeds at our Seed Swap on February 12th and you’re wondering what happens next. It all depends on what kind of seeds you’ve got.
All seeds need consistent moisture to wake up from their long sleep. Beyond that, their preferences seem to be as diverse as the plants who birthed them! One of the most important differences is the temperature they need to germinate. Our soil on Fidalgo Island often doesn’t get warm enough to germinate the seeds of long-season, heat-loving veggies in time for their crop to mature before temperatures turn cold again.
That’s why a lot of people here start these types of seeds inside under lights, on a heated propagation bench, or in a greenhouse. My rule of thumb is, if it needs to be warmer than 70 degrees to germinate, I start it indoors or in a sheltered/heated outdoor space. If you don’t want to do that, you should buy starts for those types of plants at a plant nursery.
Remembering which seeds prefer which conditions can be a challenge. I’ve made the following chart mostly for my own benefit, but I share it here in case it’s helpful to you. It’s based on back-of-the-seed-packet info, my own experience, and Linda Gilkeson’s excellent book Backyard Bounty. I’ve organized the information by what comes first in my own gardening calendar.
This isn’t an exhaustive list. You can grow different stuff than I do, or do it at different times (for example, I grow root veggies and brassicas in the winter rather than the summer because it makes them sweeter and lines up better with their natural life cycles). And remember, you don’t have to grow everything (I sure don’t)! Just grow what you like best. One more note: I tend to plant things out really small… like, a few inches tall with just a couple sets of true leaves. If you plan to start seeds indoors and want bigger plants by the time you set them out, you should start them a few weeks earlier than I do.
| Variety | Start inside by… | Pre-Treatment? | Ideal Soil temp | Plant outside by… |
| Broad beans (favas) | n/a (direct sowing is better) | Soak 8 hours | 40s+ | February |
| Alliums (leeks, onions, shallots, chives) | February | None | 60s | April to early May |
| Hardy annual wildflowers (poppies, lupine, larkspur, nigella, bachelor buttons, calendula, ammi, yarrow) | n/a (direct sowing is better, these seem to resent transplanting) | They want to freeze and thaw before sprouting, so if you don’t sow them in fall or winter, stick them in the freezer for a few weeks before broadcasting. | 50s – 60s | February |
| Peas | (pre-sprouting in vermiculite one week before planting is optional) | Soak 8 hours, pre-sprout in vermiculite if you’re worried birds will eat them. | 40s-80s | March |
| Snapdragons | March | Needs light to germinate; don’t cover | 60s | April |
| Nightshades (tomatoes, peppers, eggplants) | March | None | 70s-80s | April to early May (not before soil is warm enough for bare feet) |
| Salad greens (lettuce, spinach, arugula, etc) | n/a (direct sow instead) | None | 60s-70s | April |
| radishes, and salad turnips | n/a (direct sow instead) | None | 60s | April |
| Nasturtiums | n/a (direct sow instead, because germination is slow and erratic) | Nick them with a knife or nail file and then soak for 24 hours | 60s+ | April |
| Asters (sunflowers, zinnias, cosmos) | April | None | 70s | May |
| Corn | April | Soak 24 hours | 70s-80s | May |
| Beans | n/a (indoor pre-sprouting in vermiculite is optional) | Soak 8 hours, pre-sprout in vermiculite if you’re worried birds will eat them | 60s-80s | April and May |
| Cucurbits (cucumbers, melons, squash) | April | None | 70s-80s | Mid to late May |
| Winter brassicas (kale, cabbage, collards, radish, cauliflower, broccoli, pac choi, brussels sprouts, turnip, rutabaga, kohlrabi) | n/a (direct sow, the soil is warm enough now and the wild ones are dropping their seeds) | None | 70s | June |
| Winter root veggies (plus chard and orach, which are kin to beets) | n/a (direct sow instead, it’s warm enough now and the wild ones are dropping their seeds) | Pre-soak beets and chard, fussy procedure is optional with carrots | 70s | Early July |
| Winter salad greens (lettuce, spinach, arugula) | n/a (direct sow instead) | None, but it can help to cover the bed with shade cloth to lower the temperature and retain moisture | 60s-70s | August and September |
What if you want to start more heat-loving seeds than you have space for inside your house, but you can’t fit a greenhouse in your yard? I ran into the same problem. My solution was to build a heated propagation table under the eaves against the south side of my house. Next week on the blog I’ll share my photos of that process, along with step-by-step instructions, so stay tuned!
thank you for all these details on planting, so helpful!
I was wondering if you inoculate your peas and bean seeds before planting?
I keep reading about this step for a better crop yield and wonder if it’s really necessary.