Preparing Your Garden for Early March Planting

Early March is prime time for prepping your garden beds, especially if you’re in North Jersey or NYC. With the right steps, you can kickstart the growing season and get cool-season crops like spinach, carrots, peas, and radishes off to a strong start. Let’s dive deeper into the nitty-gritty of when and how to plant these early crops and give them the care they need.

Which Crops to Seed Now?

Cool-season crops are hardy enough to handle the lingering chill of early spring, but not all of them thrive at the same time or temperature. Here’s a quick rundown of some great options to direct-seed in March and how to handle them:

  1. Spinach

    • When to Plant: As soon as the soil is workable—typically in early March.
    • How to Plant: Sow seeds 1/2 inch deep and about 2 inches apart in rows. Thin seedlings to 4–6 inches apart once they’ve sprouted. If you're doing Square Foot Gardening 3 rows of 3 spacing
    • Pro Tip: Spinach loves cool soil (around 40–75°F). Cover it with a light row cover or cold frame to protect it from unexpected frost and speed up germination.

  2. Carrots

    • When to Plant: Direct seed as soon as the soil is dry enough to work, ideally mid to late March.
    • How to Plant: Sow seeds 1/4 inch deep and spaced 2–3 inches apart in rows. Cover lightly with fine soil or compost and water gently. For SFG 4 rows of 4 in a square foot.
    • Pro Tip: Carrots take longer to germinate (up to 3 weeks), so keep the soil consistently moist during this period. You can cover the rows with a wooden board or burlap to retain moisture—just remove it once the seedlings appear.

  3. Peas

    • When to Plant: Early to mid-March, depending on the soil temperature (it should be above 40°F).
    • How to Plant: Sow seeds 1 inch deep and about 2 inches apart in rows. If using trellises, place them when planting to avoid disturbing roots later. For SFG plant then along the back row near your trellis if you have one. If you need helping building one check out my Ultimate Square Foot Garden Bed Plans.
    • Pro Tip: Choose varieties suited for early spring, such as sugar snap or shelling peas. Protect seedlings with a cold frame or frost cloth if nighttime temperatures dip below freezing.

  4. Radishes

    • When to Plant: Early March, alongside spinach and peas.
    • How to Plant: Sow seeds 1/2 inch deep and spaced 1 inch apart. Thin seedlings to 2–3 inches apart after germination. For SFG plant 6x6 or 4x4 depending how big the variety is.
    • Pro Tip: Radishes grow fast (20–30 days to maturity), making them a great crop to interplant with slower-growing vegetables like carrots.

  5. Lettuce and Salad Greens

    • When to Plant: Early March, as soon as the soil can be worked.
    • How to Plant: Sow seeds 1/4 inch deep and thin to 6–12 inches apart, depending on the variety. for SFG I plant 4x4 to 2x2 depending on variety and how soon I pick them. Things like arugula that I pick when still young will be 6x6.
    • Pro Tip: Use a mix of leafy greens for variety, and succession plant every 2–3 weeks for a continuous harvest. If you're doing SFG you can either divide the square in half for succession planting or use multiple squares planted at different times.

Preparing to Seed: Timing Is Key

Here’s a simple rule of thumb: if your soil is dry enough to crumble in your hand, you’re ready to plant. Frost is still a concern in March, so be ready to protect your seeds and seedlings on colder nights. Keep a frost cloth or your cold frame handy to keep them cozy when temperatures drop.

Tips for Better Germination

  1. Warm Up Your Soil: If your beds are still on the cold side, lay down a sheet of black 2ml or thicker plastic for a few days before planting to trap heat. This can help raise the soil temperature just enough to give seeds a better start.

  2. Keep the Soil Moist: Seeds need consistent moisture to germinate. Water lightly every day or two, especially if the weather is dry. Use a gentle watering can or a spray nozzle to avoid washing the seeds out of place.

  3. Mark Your Rows: Tiny seeds like carrots and lettuce can be hard to spot as they germinate. Use markers or string to keep track of where you planted so you don’t accidentally disturb the rows.

  4. Succession Plant: For crops like spinach, lettuce, and radishes, plant a new batch every 2–3 weeks to ensure a continuous harvest throughout spring.

What to Watch for After Planting

  • Frost: Use your cold frame, frost cloth, or even an overturned bucket to shield young seedlings on particularly cold nights.
  • Pests: Early spring pests like aphids and slugs might show up as temperatures warm. Inspect your seedlings regularly and take action early—hand-picking or organic pest deterrents usually do the trick.
  • Thinning: Don’t skip thinning! Crowded seedlings will compete for nutrients and water, leaving you with weaker plants and smaller harvests.

With your garden beds prepped and your seeds in the ground, you’re officially kicking off the growing season. There’s something so rewarding about these early plantings—they signal the start of another year full of possibility. So grab your seeds, keep an eye on the weather, and get ready to welcome a burst of green to your garden.

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