Should You Start Lettuce Indoors? Tips for Success

This week’s 5-Minute Friday Gardening Tip Video is all about starting lettuce seeds indoors every year. I don’t grow all of my plants indoors, but I do start some of my lettuce seeds there.

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In our 5 Minute Friday Gardening Tip video this week, I talk about why I think you should start lettuce seeds inside. I don’t start all my lettuce indoors but I do grow quite a bit each year. Check out the video below:

Turns out that starting lettuce seeds indoors can be a bit of a controversial topic in gardening. There are a few reasons why I start dozens of lettuce seedlings indoors every year, but some people think I’m crazy.

They say that planting lettuce in the garden does better, so why waste space starting lettuce seeds indoors? I agree with them.

If you plant lettuce seeds right in the garden soil, they will germinate quickly and grow very well. Every year we grow at least 60 lettuce plants, and I plant most of them right in the garden soil.

However, there are times when it is really nice to have some seedlings to put out. So here are my three reasons why I think you should be starting lettuce seeds indoors this year.

I begin starting lettuce seeds around January 15th of every year. Right now, as I write this, I have 12 lettuce seedlings that are about a week old outside in the seed starter. These seedlings will go out into our cold frames roughly on March 1st.

Putting lettuce seeds to work inside in January is because I want to harvest lettuce extra early. Even in January and February, it is still too cold for seeds to sprout in my cold frames.

Even in the cold frames, the soil is still in the 40s, which is too cold for seeds to consistently grow. So the only way I can have early lettuce is by starting lettuce seeds indoors.

Around March 1, the seedlings I plant inside will be ready to move out into the cold frames. By then the temperatures in the cold frames are perfect for growing lettuce. I follow my January 15th planting with 2 more plantings on February 1st and February 15th.

This gives me a bunch of lettuce plants to put out early in the cold frames. They will all mature at different times, giving us a great harvest six weeks earlier than if we planted them in the garden.

If you plant your garden in a series of steps, you might not always have enough room to plant lettuce seeds. Fall is a great example of that in our garden. About eight weeks before our first frost is the best time to plant fall lettuce in our garden. That date is August 1st. But at that time our garden is still packed with warm-season plants.

There isn’t a lot of room in the garden to plant lettuce seeds, so I start them indoors to get a head start on my fall lettuce crop without taking up too much room. The seedlings you planted on August 1 (and 15) will be big enough to put in the garden on September 15 (when the weather starts to cool off).

It’s the best time to grow lettuce!! By mid-September, most of my warm-season crops are ready to be pulled out of the garden to make room for lettuce plants and other fall crops.

Lettuce is a cool-season crop that thrives in spring and fall. As temperatures rise into summer, lettuce will bolt and become bitter. Many gardeners start lettuce seeds indoors to get a head start on the growing season for earlier harvests. But is this necessary? Here is a complete guide to whether and how to start lettuce indoors.

Should You Start Lettuce Inside?

Lettuce can be directly sown into the garden or started ahead indoors – both methods will work. Here are some factors to help decide which is best for you:

  • If you have a short growing season, starting indoors extends harvests by a few weeks.

  • Indoor seeding avoids predation of tender seedlings by slugs or insects outside

  • You can provide consistent moisture and ideal temperatures for germination indoors,

  • Starting inside requires grow lights and space for seedlings over 6-8 weeks.

  • Hardening off and transplanting seedlings takes time and care.

Either way, lettuce thrives when temperatures are between 45-75°F. Time indoor planting so lettuce reaches optimal size as the weather warms up for transplanting.

Timing When to Start Lettuce Indoors

  • Count backwards – lettuce takes 5-7 weeks to reach transplanting size from seed.

  • Factor in 1-2 weeks to harden off seedlings before transplanting outside.

  • Transplant lettuce 1-2 weeks before the last expected spring frost.

  • For fall crops, sow indoor seeds 10-12 weeks before the first fall frost.

Adjust timing as needed for your climate and target harvest dates. Be patient – lettuce grows quickly once established in the garden.

Step-by-Step Guide to Starting Lettuce Inside

Follow these tips for success with indoor lettuce planting:

Grow Setup

  • Provide full spectrum grow lights close to seedlings – LEDs work well and stay cool.

  • Maintain room temperatures between 65-75°F for optimal growth.

  • Set lights on a 16 hour on/8 hour off daily cycle if lacking natural light.

Planting

  • Sow seeds in sterile seed starting mix in cell trays or containers. Cover seeds lightly.

  • Water gently with a spray bottle to avoid displacing small seeds.

  • Place trays in warm area (70°F+) until sprouted, then move to grow lights.

Seedling Care

  • Keep soil moist but not saturated to prevent damping off disease.

  • Feed with diluted liquid fertilizer once true leaves emerge.

  • Gradually expose to outdoor conditions 1-2 weeks before transplanting.

Transplanting

  • Harden off by placing seedlings outdoors in partial shade for a few hours.

  • Increase outdoor time over a week or two until seedlings acclimate.

  • Transplant on a mild, cloudy day into moist soil. Water and provide shade.

With the right indoor conditions and timing, you can grow sturdy lettuce seedlings ready to finish maturation in the garden.

Tips for Transplanting Lettuce

Reduce transplant shock and help seedlings establish quickly with these tips:

  • Water seedlings well the day before and DAY of transplanting.

  • Gently loosen and remove seedlings to avoid root damage.

  • Transplant on an overcast, calm day, preferably in late afternoon.

  • Set seedlings at the same level they grew at indoors. Firm soil around roots.

  • Water immediately and provide shade from hot sun for a few days.

  • Watch closely and continue to water when top inch of soil is dry until established.

  • Place cutworm collars around seedlings if pests are an issue.

With proper hardening off and ideal transplanting conditions, indoor-started lettuce will flourish.

Bottom Line on Indoor Lettuce

Start lettuce inside if:

  • You want earlier maturity and extended harvests from transplants.

  • Your outdoor growing season is very short.

  • You have problems with insects or critters eating seedlings.

  • You have space, time, and resources for quality indoor conditions.

Sow lettuce directly outdoors if:

  • You have 3-4+ months of optimal spring/fall growing temperatures.

  • You lack indoor growing facilities and can directly sow outside.

  • You want to skip fussing with transplants and seedlings indoors.

  • You don’t mind later maturity dates from direct sowing.

Either way, provide lettuce with rich soil, ample moisture, and protection from hot sun. In suitable conditions, it will grow quickly and reward you with healthy, tasty, homegrown leaves!

3 – Better Finished product

I am terrible at thinning. Lettuce seeds are small and hard to plant and my outdoor planting usually looks like this:

should lettuce be started indoors

This lettuce is fine, but it’s a bit crowded, so the leaves will be small and don’t shape right.

There are times when you really want a nice-looking finished head of lettuce. I’m talking a really big head of butter crunch lettuce, or maybe a nice tall head of romaine.

It is much easier to get that really good finished head of lettuce by starting lettuce seeds indoors. You can better keep an eye on the plants if you start them indoors and then move them to the garden when they are about 6 weeks old. Starting lettuce seeds indoors leads to a really nice-looking finished product.

should lettuce be started indoors

How to Grow Lettuce Indoors – Gardening Year-Round

Can you grow lettuce indoors?

Grow lettuce indoors in a hydroponic garden, in a pot or container, or in a grow tent. Keep your plants strong and have lettuce year-round. From seed to seed starting, to harvest, lettuce is a lot of fun to cultivate. And it’s healthy. If you have lettuce to grow, then there’s no excuse not to incorporate this crunch in your meals!

Can you grow lettuce from seed?

Lettuce is grown from seeds or transplants. Seed is viable for 5 years. Start lettuce indoors 4 weeks before transplanting; sow or transplant lettuce into the garden as soon as the soil can be worked. Seed germinates in 2 to 10 days at or near 70°F (21°C)—but sometimes seed can take up to 2 weeks to germinate if the soil is cold.

Can you grow lettuce in winter?

In cold winter regions, grow lettuce in spring and autumn. If you want to grow lettuce in summer, plant heat and bolt-resistant varieties. Good Products for Growing Your Garden: Sow lettuce seeds directly in the garden 4 to 6 weeks before to 3 weeks after the last frost in spring. Start transplants indoors 4 to 6 weeks before setting out.

How do you care for lettuce indoors?

Caring for lettuce, as you’re growing it indoors, is an extremely basic process. The crop will need light, fertilizer, and water. To start, make sure the crop is consistently moist. Lettuce has shallow roots. Therefore, it’s better to water it briefly every day.

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