Let’s Get Growing!
It’s time to get growing! March in Zone 6a is veggie garden prep season. While the weather is unpredictable, luckily spring is inevitable. If you’re growing from seed, now is the right time to start planning and planting.
For specific instructions and timing, it is always best to check your individual seed packet instructions—but this quick overview is a good guide for planning.
Indoor Seed Starting
Starting seeds indoors gives you a jump on the season, allowing for early growth and production. Our last frost usually hits Zone 6a in mid-May (right around Mother’s Day), which means mid-March is the ideal time to start many warm-weather herbs and veggies. Remember that not all plants handle being moved (we’re looking at you, carrots and string beans), but for those that do, starting indoors is a great way to go.
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Tomatoes, peppers, basil, squash, cucumbers, and eggplants transfer well and need about 8–10 weeks of indoor growth before moving outside. These are sensitive plants and should not be transplanted until after the last frost.
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Broccoli, cabbage, parsley, Brussels sprouts, and kale are hardier and can be transplanted to the garden as early as late April.
While the head start is nice, indoor seedlings get a little “spoiled” by stability. When it’s time to transfer them outdoors, you should plan to “harden” them off, as moving them directly into the garden can cause transplant shock or death. Here is a basic step-by-step on how to harden off your indoor seedlings:
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Days 1–2: Place plants outside in a shaded spot for a few hours, then bring them back in.
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Days 3–4: Increase outdoor time a little more, allowing them to sit in dappled or very brief direct sunlight.
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Days 5–6: Leave them out for about half the day, introducing more direct sun.
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Days 7+: If the forecast is clear of frost, leave them out all day and eventually overnight. They are now ready for the garden.
Outdoor Direct Sowing
It might seem early, but some seeds are ready to be planted outside as soon as the soil is workable (meaning not frozen or soaking wet). Here are a few varieties that can go directly into the ground:
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Peas are often the first thing people plant. The old adage is to plant your peas by St. Patrick’s Day. Since peas tend to fizzle out in the heat, getting them started early ensures a good harvest before summer hits. Onions and seed potatoes can also do well when planted early.
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Spinach and cold-tolerant lettuces can handle cold soil very well and will benefit from an early start.
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Beets, radishes, carrots, and other root veggies should go out toward the end of March through mid-April.
General Seed Starting Advice
Soil Selection and Garden Prep
Choosing the right soil can help your seedlings get off on the right foot. Remember, we happily offer free pH soil testing. The best time to amend your soil is before your seeds or plants go in the ground.
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If you’re sowing indoors: Coast of Maine’s Sprout Island Seed Starter Blend is a fantastic choice for successful seed germination. It’s fortified with worm castings and kelp meal, and we have had nothing but positive feedback.
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For garden beds: Top-dress beds with organic compost to replenish nutrients before you start planting. We highly recommend Coast of Maine’s Quoddy Compost Blend for in-ground or raised-bed gardens. Local municipalities also sometimes offer free compost for residents; mixing both can be a great way to maximize nutrients while filling large gardens affordably.
Early Watering Advice
Whether planting inside or out, watering habits help determine your success. Direct sowing in March is a balancing act since the soil is often naturally damp from snowmelt and rain. Indoors offers a bit more control.
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If you’re planting outside and your hose is set up, use a gentle mist setting for newly sown seeds. Otherwise, use a watering can with a fine spray. Heavy streams can wash away tiny seeds like carrots or lettuce. Indoors, this is easily achieved by using a spray bottle.
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Before watering outside, stick your finger about an inch into the soil. If it feels moist, skip watering. Overwatering in cold weather can lead to problems. Indoors, follow the same advice, but remember that soil can dry out quickly, so check frequently.
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If you are planting outside, water in the morning if possible. This allows the foliage to dry during the day, which helps prevent fungal diseases that thrive in the cold, wet night air. Indoors doesn’t have the same challenges, so water when you’re able.
Weather, Light, & Transplanting Tips
While Mother’s Day is a common benchmark for moving plants outside, overnight, “cold snaps” can occur through June 1st.
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Whether you are transplanting seedlings from indoors or direct sowing, using row covers or cold frames can help create favorable conditions earlier in the spring and protect against sudden temperature drops.
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Once seeds sprout, they will be looking for light in order to grow. Most edibles require at least 6 hours of direct sun daily to thrive. If you are planting outside, choose a spot that gets this light. If you are planting indoors and don’t have a bright, south-facing window, seedlings will become “leggy” (tall and weak). You can use a grow light for 14–16 hours a day to ensure sturdy seedlings.