Greenhouse Gardening in Spring: What to Plant Now
Spring is a favorite season of many in the greenhouse. Everything feels fresh and full of possibility! If you're anything like me, you’ve probably been counting down the days to get your hands back in the dirt more and more. But as those warmer days sneak in and cooler nights linger, knowing what to plant — and when — can make all the difference in having a thriving greenhouse this spring.
Today, I’m breaking down the BEST cool and warm season crops for this tricky time of year, based on what’s working in my own Yoderbilt Greenhouse right now!
Why Spring Greenhouse Gardening is a Game-Changer
I still remember my first spring with a greenhouse — I was beyond excited but also a little overwhelmed trying to figure out what I could actually grow in early spring versus what needed to wait. Here in Arkansas (Zone 7b), our spring weather can flip from 40°F mornings to 75°F afternoons in a heartbeat, and a greenhouse helps buffer those extremes beautifully. But it also means you need a game plan for both cool-loving plants and those heat seekers you’re ready to get started.
So if you’ve ever asked:
- "What should I plant in my greenhouse in March, April, and May?"
- "Can I start tomatoes in the greenhouse this early?"
- "Which greens do best in a spring greenhouse?"
You’re in the right place — let’s dive in!
Cool Season Crops to Plant Now (March & Early April)
Cool season crops are the superheroes of early spring, loving those cooler nights and thriving in the gentle warmth of a greenhouse. These are the crops I’m harvesting or growing right now:
Lettuce
- Buttercrunch, Romaine, and even baby mixes.
- I sow in soil blocks and trays and move them into raised beds and containers inside the greenhouse.
Pro Tip: Succession plant every 2-3 weeks for a steady harvest.
Spinach
- Loves that lingering chill and grows fast under cover.
- I like "Bloomsdale Long Standing" for its crinkly leaves and cold tolerance.
Broccoli and Cabbage Starts
- While these will eventually head out to the garden, I start them in the greenhouse for stronger transplants.
- Broccoli loves greenhouse mornings and will grow faster in a protected space before moving outside.
Carrots in Grow Bags
- Yes, carrots! If you have deep grow bags or raised beds, you can get an early crop of baby carrots.
- Try "Parisian" or "Little Finger" varieties for faster harvests. If you’ve never eaten a home grown carrot, you will never want a grocery store carrot again.
Herbs: Parsley, Cilantro, Dill
- These herbs love the cool air and are much slower to bolt inside a greenhouse in early spring.
- There is nothing like snipping fresh dill for a spring salad!
Tomatoes
- Cherry, slicers, and paste tomatoes all do fantastically in a greenhouse setting once nighttime temps are above 50°F consistently.
Pro Tip: Start them indoors on heat mats if nights are still dipping too low, then move them to the greenhouse to size up before final planting.
Peppers
- Bell, jalapeño, banana — peppers are heat lovers, but the greenhouse gives them a jumpstart.
- My "must-have" this year is Carnival — a sweet pepper that is great for summer dips.
Warm Season Crops to Start (Mid-April to May)
Once we start getting consistent warmer days, I start transitioning to warm-season crops. Some I start from seed, others from starts. Here’s my go-to list for those "can't wait to grow them" veggies:
Cucumbers (Bush and Trellis Varieties)
- "Marketmore" for slicing, "Mini Munch" for snacking.
- Start inside, and once days hit 70°F+, they’ll take off.
- I transplant mine outside once the danger of frost has passed.
Pro Tip: Trellis them up to save space!
Zinnias and Cut Flowers
- Okay, not veggies — but you need flowers too!
- I start zinnias, cosmos, and marigolds in the greenhouse so they’re ready to explode in the garden.
- And yes, some I leave in pots inside the greenhouse for early color!
Melons (Optional for Bigger Greenhouses)
- If you have space, try a small cantaloupe or personal watermelon variety.
- The controlled heat and humidity of a greenhouse can extend melon season earlier.
- Carrots in Grow Bags
Personal Lessons Learned: What I Wish I Knew My First Spring
If I could go back and tell myself one thing that first spring? Don’t be afraid to overlap cool and warm crops in April!
I used to think I had to fully clear out my lettuce before starting tomatoes — but now I plant around the edges and harvest lettuce while tomatoes grow bigger in the same bed. Talk about space efficiency!
