Seed Starting Supplies: Everything You Need to Grow from Seed

Count backward from your last frost date. Most transplants go outside 1-2 weeks after last frost. Seed packets tell you weeks-before-transplant timing. General guidelines: Tomatoes/peppers: 6-8 weeks before transplanting. Eggplant: 8-10 weeks. Lettuce/greens: 4-6 weeks. Herbs: 6-8 weeks. Squash/cucumbers: 3-4 weeks (don't start too early - they grow fast). Broccoli/cabbage: 6-8 weeks. Check your local last frost date and work backward.

It depends on what you're growing and your home temperature. Heat mats are very helpful for: warm-season crops (tomatoes, peppers, eggplant) that germinate best at 75-85F, and any seeds when your home is below 70F. Not necessary for: cool-season crops (lettuce, broccoli, spinach) that germinate at 60-75F, or if your home stays consistently warm. Heat mats typically raise soil temperature 10-20F above ambient. They significantly speed germination and improve germination rates for warm-weather crops. Worth $15-30 investment if growing tomatoes/peppers.

Seed starting mix should be: fine-textured (no large bark chunks), sterile (no disease or weed seeds), lightweight (won't compact), and low in nutrients (seedlings don't need fertilizer until true leaves appear). Commercial seed starting mixes work great. You can make your own: equal parts peat moss (or coco coir) and fine vermiculite or perlite. Don't use regular potting mix - it's often too chunky and rich for tiny seeds. Don't use garden soil - it compacts and may contain pathogens. Moisten mix before filling trays.

General rule: Plant seeds at a depth of 2-3 times their diameter. Tiny seeds (lettuce, basil): barely cover with mix or press into surface. Small seeds (tomatoes): 1/4 inch deep. Medium seeds (peppers, eggplant): 1/4 - 1/2 inch deep. Large seeds (squash, beans): 1/2 - 1 inch deep. Some seeds need light to germinate (lettuce, some herbs) - press onto surface but don't cover. Check seed packet for specific instructions. When in doubt, shallower is safer - seeds planted too deep may not have energy to reach the surface.

Leggy seedlings (tall, thin, pale stems) are caused by insufficient light. Seedlings stretch toward light, growing tall and weak instead of short and stocky. Solutions: Move lights closer (2-4 inches above seedlings), increase light duration (14-16 hours), add more/stronger lights, or move to brighter location. Other contributing factors: too warm after germination (cool temperatures produce stockier plants), overcrowding (thin to one seedling per cell), and starting too early indoors. Severely leggy tomato seedlings can be transplanted deeply - bury stem up to first leaves.

Budget seed starting setup ($15-30): DIY containers: egg cartons, yogurt cups, newspaper pots (all free). Reused containers from previous years. Growing medium: Budget seed starting mix ($5-8) or DIY mix of peat and perlite. Light: South-facing window works for some crops, or basic LED shop light ($15). Heat: Warm spot on top of refrigerator, near heating vent, or on a warm appliance. Humidity: Cover with plastic wrap instead of dome. Skip the heat mat for cool-season crops. Upgrade components as you learn what your setup needs.