If Collie Flowers Can't Help You Grow A Cauliflower, The Who Can? - Brassica Growalong (part 1)

Replicated from an article I wrote for Garden Folk Magazine, February 2026.

I’m Nic, a self-confessed seed obsessive. I know a lot of us say that, but I took my obsession to the next level when 4 years ago I started working on a little project to research and collate a library of sowing and growing information that eventually became Collie Flowers; a small independent seed supplier. Beyond premium seeds, everything about Collie Flowers is focused on equipping you with the gardening knowledge you need to succeed.  

I’m delighted that Ally and Anjee have invited Collie Flowers to host the GFM Growalong for 2026 and they’ve told me they’d like to help their readers with growing an outstanding collection of Brassicas – after all if Collie Flowers can’t help you grow a Cauliflower then who can? 

When I first started allotmenting I knew I’d properly got the gardening bug when I was regularly bringing home sprouts and cabbages, things we eat and are often thought of as “old-school grow your own staples”. The joy of your first proper cauliflower head, not one that’s tiny, or a bit chomped, or sun damaged or been left a day too long and starting to bolt is unparalleled! Although the shame when your husband bans you from ever growing Kale again because you released a million white fly into the kitchen is not great, and hopefully one we can avoid you facing. 

I can sense already some of you are starting to think “but Brassicas are notorious for being difficult to grow”. So before we even think about starting to sow some, let’s unpack that and set you off on the road to success. 

Brassicas (cabbages, kale, broccoli, sprouts, cauliflower, and more) have a reputation for being a bit tricky. And it’s true that they’re not as carefree as lettuces or beans. But “difficult” isn’t quite the right word. Brassicas are particular. Once you understand what they need, they’re some of the most rewarding, productive crops you can grow. They thrive in fertile, well draining soil, are hardy, nutrient‑dense, and many varieties will keep you in greens for months. 

They’re also brilliant for UK conditions - cool summers, damp springs, and long autumns suit them perfectly. Let’s keep our fingers crossed that 2026 gives them what they need, because 2025 certainly didn’t! 

So why do they get this reputation? It usually comes down to a few very specific challenges... 

They attract pests: Cabbage worms, caterpillars, aphids and other brassica‑loving insects can cause real damage if plants aren’t protected early on. 

They’re vulnerable to soil‑borne diseases: Clubroot, black rot and downy mildew are common issues, especially in gardens where brassicas have been grown repeatedly without rotation. We’ll talk about polyculture and companion planting and how they can help alleviate this in another edition. 

Timing really matters: Many brassicas have very specific sowing and maturing windows. Choosing the wrong variety for the wrong time of year is a common cause of failure. 

They need firm soil and steady moisture: Loose soil, irregular watering or poor spacing can all lead to weak plants or bolting. 

None of these things make brassicas “hard” — they just mean they need a bit more attention to detail. 

We’ll be starting to sow seeds for the GFM Growalong in March. Month by month until we’re harvesting Brussel Sprouts for our Christmas Dinners I’ll be here setting out essential jobs for the month ahead, sharing my progress with you and answering any questions you might have. 

Before we get out hands in the compost and start sowing here are my top tips for growing healthy Brassicas  

Warm Start: While brassicas thrive in cool weather, they germinate best in with a little heat. A propagator or warm windowsill will help germination. 

Rich Soil: Brassicas love deep, fertile soil; you can improve your soil with garden lime and organic matter, such as manure and compost to ensure nutrient-rich, well-drained soil. Adding nutrients into the soil will promote health growth and should mean minimal additional feeding is needed. 

Careful Transplanting: Handle seedlings by their true leaves, not stems. Gradually move them to larger pots, planting deeper each time, and firm the soil well when transplanting outdoors to prevent wind damage. 

Harden Off: Before planting out, prepare your plants for the transition by gradually exposing them to outdoor conditions over several days. 

Wind Protection: Shelter plants from strong winds to prevent windrock, which can damage roots and stunt growth.  

Proper Spacing: Give plants ample space to grow. Packing your plants together might give ground cover but you can end up with them being overcrowded, our seed packets give you the ideal spacing to avoid overcrowding and promote healthy root spread. 

Pest Control: Protect your brassicas from pests like slugs, caterpillars, and aphids. Use netting or other pest control methods as needed. 

Timely Harvesting: Harvest crops like cauliflower and cabbage as soon as they're ready to avoid bolting and pest damage. Enjoy your brassicas at their peak! 

Choose the right variety for the right season 

Some brassicas are bred for summer harvest, others for winter. Matching the variety to the season is key. The calendar below gives you an overview of what the GFM Growalong year will look like. 

Hopefully now you’re prepared you’re not thinking that joining in with the growalong is going to be difficult! Once you’ve cracked the basics, brassicas become some of the most satisfying crops in the garden, especially when you’re explaining to someone what a Kohl Rabi is, harvesting caulis in the summer or cutting your own home‑grown cabbage for Sunday dinner. 

I can’t wait to grow alongside you this year, and if you’re new to brassicas, this is the perfect place to start.