Seeds to Start Indoors 6–8 Weeks Before Your Last Frost

Learn which seeds to start indoors 6–8 weeks before your last frost date, including tomatoes, peppers, herbs, and more. Plan your seed starting with confidence.

If you’ve been staring at seed packets, wondering Is it time yet? This is likely the window you’ve been waiting for.

The 6–8 weeks before your average last frost date is one of the most important seed-starting periods of the year. This is when many popular garden crops are started indoors so they have enough time to grow strong before being transplanted outside.

In this guide, you’ll learn which seeds to start indoors during this window, why this timing works so well, and how to set yourself up for healthy, productive plants.

Start With Your Average Last Frost Date

All seed-starting schedules are based on one key piece of information: your average last frost date.

This date tells you when it’s typically safe to plant tender crops outdoors in spring. To find yours, enter your ZIP code at PlantMaps.com or Garden.org, then count backward to determine when to start seeds indoors.

If it’s still a little early for your area, go ahead and save this post for reference. Timing varies by region, and this guide will be ready when you are.

For a step-by-step explanation of how frost dates work and how to build a complete planting plan, see: How to Create a Seed Starting Schedule Based on Your Last Frost Date.

Why These Seeds Are Started 6–8 Weeks Before Frost

This window is often considered peak seed-starting season.

Seeds started now:

• Germinate and grow quickly under lights.
• Reach transplant size as outdoor conditions begin to improve.
• Are less likely to become root-bound or leggy than seeds started too early.

Many of these crops need warm soil, steady moisture, and time to develop strong root systems, making indoor seed starting ideal at this stage of spring.

Seeds to Start Indoors 6–8 Weeks Before Your Last Frost Date

The following crops are well suited to starting indoors during this time. Each benefits from a protected environment while developing healthy roots and steady growth.

Herbs to Start Indoors

Many culinary herbs benefit from an indoor start, especially those that germinate slowly or grow more steadily in warm, consistent conditions. Starting these herbs indoors allows you to establish healthy plants early, so they’re ready to thrive once transplanted into the garden.

Basil

Basil thrives in warm conditions and grows quickly once established. Starting basil indoors helps ensure sturdy plants ready to take off once transplanted outdoors.

Oregano

Oregano grows slowly at first. An indoor start gives it time to establish before moving into the garden, especially in cooler regions.

Sage

Sage has a longer germination period and benefits from an indoor start, so plants are well established before transplanting.

Marjoram

Marjoram is closely related to oregano and shares similar growing habits. Starting it indoors allows the seedlings to develop steadily before being planted outside.

Chamomile

Chamomile seedlings are small and delicate early on. Starting them indoors makes it easier to manage moisture and light while they establish.

Greens to Start Indoors

Some greens can be direct sown outdoors, but starting them indoors allows you to grow sturdy seedlings that are ready to transplant as soon as outdoor conditions are right. Starting transplants early can help you get an earlier harvest, especially in areas with a shorter growing season.

Kale

Kale is cold-hardy, but starting it indoors helps you grow strong seedlings that can be transplanted into the garden early for an earlier harvest.

Warm-Season Vegetables to Start Indoors

Warm-season vegetables need consistent warmth and time to develop before being planted outside. Starting these crops indoors 6–8 weeks before your last frost date helps ensure healthy plants that can handle the transition to the garden once the soil warms and frost risk has passed.

Tomatoes

Tomatoes are classic candidates for indoor seed starting. Beginning them during this window gives plants time to develop sturdy stems and leaves without becoming overgrown.

Peppers

Peppers grow more slowly than tomatoes and need warm soil to germinate. This timing gives them a strong head start under lights.

Tomatillos

Tomatillos are warm-season plants that benefit from an indoor start. Starting them now helps ensure healthy growth and earlier fruiting once transplanted outdoors.

Review the Seed Packet Before You Start

Your seed packet is one of the best resources for successful seed starting. Before planting, take a moment to review the information on the packet, including:

• Timing: When to sow seeds based on your last frost date.
• Planting Depth: How deep to plant seeds for proper germination.
• Germination Time: How long seeds typically take to sprout.
• Spacing: Helpful to know when potting up or transplanting.

Seed packets can vary by variety, so always follow the instructions provided whenever possible.

Tips for Starting Seeds Indoors Successfully

To grow strong, healthy seedlings, keep these basics in mind:

• Use bright grow lights positioned close to seedlings.
• Keep soil evenly moist, but not soggy.
• Provide good air circulation.
• Label everything, even if you think you’ll remember. Some seedlings look alike early on.
• Pot up into larger containers as needed for strong, healthy transplants.

A simple grow light setup and consistent care go a long way toward producing sturdy plants.

Helpful resources:

• Using Grow Lights for Seedlings and Indoor Growing
• 10 Steps to Starting Seeds Indoors
• How to Harden Off Seedlings

Can These Seeds Be Started Earlier or Later?

Some flexibility is built into seed starting, but timing still matters.

• Herbs and kale can be started slightly earlier if you’re eager to begin.
• Tomatoes, peppers, and tomatillos are best started within this window.

Starting warm-season crops too early can result in tall, weak plants that struggle to adapt when transplanted outdoors. If you’re unsure, it’s usually better to start a little late than too early.

What to Start Next

As your last frost date approaches, more crops become ready to start both indoors and out.

Next in the indoor seed-starting schedule: Seeds to Start Indoors 4–6 Weeks Before Your Last Frost (Coming Soon).

This window focuses on fast-growing crops that don’t need as much time under lights.

And if your garden soil has drained and can be worked: Seeds to Direct Sow 6–8 Weeks Before Last Frost (Coming Soon).

Cold-hardy crops like peas, carrots, and spinach can be planted directly in the garden at this stage.

Starting seeds indoors is one of the most rewarding parts of gardening. A little planning now leads to healthier plants, earlier harvests, and a smoother transition into the growing season.

Good planning is key to a successful vegetable garden

Whether you are new to growing your own food or have been growing a vegetable garden for years, you will benefit from some planning each year. You will find everything you need to organize and plan your vegetable garden in my PDF eBook, Grow a Good Life Guide to Planning Your Vegetable Garden.