Seed starting timeline for beginners
Your first year starting seeds indoors can feel overwhelming. There are dozens of vegetables, each with different timing, and every guide seems to assume you already know your last frost date and what "weeks before transplant" means. Let me break it down simply.
The whole system runs on one date: your last expected spring frost. Everything else is just counting backward from there. If you don't know your frost date, look it up here by zip code. I'll use a May 1 last frost date for the examples below. Adjust up or down for your area.
What you actually need to start seeds
The internet will try to sell you a lot of gear. Here's what actually matters:
- A light source. This is non-negotiable. A sunny window is not enough. Seedlings need 14-16 hours of direct light. A basic shop light with two T8 or LED tubes, positioned 2-3 inches above the seedlings, costs about $25 and works fine. You don't need special "grow light" spectrum bulbs.
- Containers with drainage. Cell trays, yogurt cups with holes poked in the bottom, whatever. It doesn't matter much as long as water can drain out.
- Seed starting mix. Not garden soil, not potting soil with fertilizer. Seed starting mix is lighter and sterile. A bag costs $5-8 and lasts a while.
- A warm spot for germination. Most seeds germinate between 70-80F. A heat mat helps but isn't required for most crops.
That's it. You can spend more later if you want, but plenty of gardeners grow hundreds of seedlings under a $25 shop light on a folding table.
The timeline (based on May 1 last frost)
Here's the week-by-week breakdown. I'm only including crops that are worth starting indoors. Some things (beans, corn, squash, root vegetables) do better sown directly in the garden and I'll note those at the end.
12-14 weeks before last frost (early February)
Only one thing goes now: onions. If you're growing onions from seed (which gives you the widest variety selection), they need this much lead time. Onion seedlings grow slowly and look like grass clippings for weeks. That's normal.
Also start any hot peppers (habaneros, ghost peppers, superhots) now. They're the slowest germinators and slowest growers in the vegetable world.
8-10 weeks before last frost (late February to early March)
This is the big one. Start these now:
- Tomatoes (all types)
- Bell peppers and sweet peppers
- Eggplant
These three are the workhorses of most gardens and they all need about 8 weeks of indoor growing to reach transplant size. Sow seeds 1/4 inch deep, keep them warm (75-85F) until they sprout, then move them under lights immediately.
6-8 weeks before last frost (mid March)
Start these:
- Broccoli
- Cauliflower
- Cabbage
- Kale (though kale can also be direct sown)
These are cool-season crops that get transplanted outside 2-3 weeks before your last frost date. They can handle light frost, so they go out earlier than tomatoes and peppers.
4-6 weeks before last frost (late March to early April)
Start these:
- Lettuce and salad greens (for transplanting, though direct sowing also works)
- Swiss chard
- Herbs: basil, parsley, cilantro
Basil is frost-sensitive and goes out the same time as tomatoes. Parsley is slow to germinate (2-3 weeks), so don't panic if nothing shows up for a while.
2-4 weeks before last frost (mid April)
Start these:
- Cucumbers
- Squash and zucchini
- Melons
These grow fast and hate having their roots disturbed. Start them in larger pots (3-4 inch) and transplant carefully. Honestly, for your first year, you might want to just direct sow these. They catch up quickly when sown in warm soil after frost.
What to direct sow instead of starting indoors
Some crops do better planted straight into the garden:
- Beans (bush and pole): direct sow after last frost
- Corn: direct sow after last frost, soil needs to be 60F+
- Carrots: direct sow 2-3 weeks before last frost
- Peas: direct sow 4-6 weeks before last frost (they like cool weather)
- Radishes: direct sow anytime from 4 weeks before frost onward
- Beets: direct sow 2-3 weeks before last frost
The two biggest beginner mistakes
Starting too early is mistake number one. It's tempting to start tomatoes in January. Don't. By May, they'll be leggy, rootbound, and stressed. A tomato started 8 weeks before transplant will outperform one started 14 weeks before. Every time.
Not enough light is mistake number two. Seedlings on a windowsill stretch toward the glass, get thin and floppy, and fall over. This is called being "leggy" and it's almost always a light problem. Get your shop light within 2-3 inches of the seedling tops and keep it on for 14-16 hours a day. Use a cheap timer.
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Keep it small your first year
Pick 4-5 crops. Tomatoes, peppers, and a few herbs are a great starting set. You can add more next year once you know how much space your lights can handle and what the transplanting workflow feels like. Starting seeds is one of those skills that gets dramatically easier with a single season of practice behind you.