Overwintering Brassicas: Start Now for Spring
Last March I walked out to the garden and the sprouting broccoli was just going absolutely berserk. Purple side shoots everywhere, the plant looking somehow smug about surviving three months of grey nothing. Meanwhile my neighbor was inside flipping through seed catalogs, two months away from his first harvest. That’s the whole game right there.
Overwintering brassicas are the long con of the vegetable garden. You start them now, in July, and by February or March when the rest of your garden is a muddy rectangle of regret, these plants are already delivering. It’s called the hungry gap for a reason. This is how you fill it.
What You’re Actually Growing
The stars of the overwintering show are purple sprouting broccoli, kalettes (which are kale crossed with Brussels sprouts and genuinely taste better than either), and the hardier cabbages. Also kale, obviously, though kale barely needs your help. Kale just exists, unbothered, through whatever winter throws at it.
Purple sprouting broccoli is the one that gets people hooked. Unlike heading broccoli that gives you one main head and then slowly disappoints you, PSB throws cut-and-come-again side shoots for weeks. The more you pick, the more it produces. Which, if you think about it, is basically the ideal vegetable personality.
Why July Planting Actually Matters
Here’s what I got wrong the first time: I thought I could just direct sow these in September and call it good. Planted them all late and spent the winter watching tiny sad seedlings that never got big enough to really take off in spring. They need to go in the ground as established transplants before the cold sets in, not after.
The goal is a plant that’s big and sturdy, maybe 8-10 inches tall, before temperatures drop hard. That means starting seeds now in July, getting them to transplant size in August, and getting them in the ground by late August or early September. The plant then hunkers down, slows way down in winter, and the second the days start lengthening it just explodes. The root system is already there. It doesn’t have to start from scratch.
A spring-sown brassica in January is just playing catch-up the whole season. The overwintered plant already won the race before the race started. (If you’re already thinking about other crops to sow this month, this post on July seeds for fall harvest is worth a look too.)
Starting Your Seeds
Sow into small containers or a seed tray right now. I use whatever pots I have lying around and coconut coir for starting mix because it drains well and doesn’t compact. Brassica seeds germinate fast in warm July soil temps, usually within 4-6 days. They practically jump out of the ground.
Give them a few weeks in a tray, prick out the strongest ones into individual pots when they have their first true leaves, and grow them on somewhere with good light. They don’t need a grow light at this time of year. A sunny porch or cold frame works fine. The Pacific Northwest summer is actually ideal for this, warm enough to get good growth, not so scorching that the seedlings fry.
Transplanting and Spacing
These are big plants. That’s the thing people consistently underestimate. Purple sprouting broccoli especially will get 2-3 feet tall and almost as wide. Give them at least 18 inches between plants, 24 if you can spare it. I crowded mine the first year and they still produced, but the air circulation suffers and you start getting more pest pressure.
When you transplant in late August, dig the hole a bit deeper than the root ball and plant them slightly low. Firm the soil around the stem well. These plants are going to face some wind and rain over the next few months and a loose root system is going to wobble. I usually stake mine loosely just to be safe, especially the taller varieties.
Water them in well and then, honestly, mostly leave them alone. A little feed in autumn before growth slows helps. After that they just sit there looking vaguely ominous through December and January. Don’t panic. They’re fine.
The Payoff
Come February, watch closely. The first shoots appear almost apologetically at first, just little nubs. And then the whole plant shifts into a different gear. Harvest the shoots when they’re tight and before the yellow flowers open. Steam them, roast them, eat them straight in the garden if nobody’s watching. My daughters do this every spring and I pretend to be annoyed about it.
If you’re already planning for spring in other parts of the garden, sowing spinach in late August pairs really nicely with this strategy. Same patient-gardener energy, similar hungry-gap payoff.
Start the seeds now. The patience part comes later. But honestly, the patience is way easier when you know what’s waiting on the other side of February.
Photo by Sandie Clarke on Unsplash
