Four weeks is possible. But I wait six. Here’s why
In near-perfect conditions, a lettuce seedling is big enough to move into either a garden, allotment or container about four weeks after planting. Here’s the complete timeline:
- Week 1: Most seeds sprout within four to seven days.
- Week 2: The sprouts develop their first set of true leaves.
- Week 3: Growth picks up. Many seedlings have several sets of true leaves, and by the end of the week, some may already be ready to transplant.
- Week 4: Growth accelerates even more. By the end of this week, most seedlings are typically transplant-ready.
Yes, You Can Transplant After Four Weeks…
After four weeks, you absolutely can transplant them into their final growing space. Technically speaking, they are ready and will adapt just fine. But in real-life growing conditions, I still consider the plants too small, tender and vulnerable. A single hungry slug or snail could wipe them out overnight.
But Here’s Why I Wait Six Weeks
That is why I like to give my lettuce seedlings a bit more time (usually an extra week or two) before moving them. And its not just about protection. It is also about not disrupting their growing momentum. Around week 4, the plants start hitting their stride. Growth takes off. They are gaining strength and expanding their roots faster than ever!
So, I let that growth play out for a little longer. And when I finally do transplant them, they are stronger, sturdier and far better prepared to handle their new environment. They are in a much better position to survive any setbacks (like a slug attack or two) that might otherwise break them.
What It Takes To Hit That Four-Week Mark
I have grown lettuce seedlings from seed to transplant-ready size in just four weeks. I did it many, many times. It definitely can be done. And it is not difficult either. But, like I mentioned, the conditions need to be perfect. Or at least very close to it. That means:
- The right temperature.
- The right light.
- The right potting mix.
- The right variety.
- And just enough water.
Why It’s Slower Outside
For me, the easiest way to get all the things right is indoors under grow lights. There, I can fully control both light and temperature as well. I don’t have that privilige outside, though. Early in spring (when it is prime time to start lettuce seeds) temperatures often dip below 10°C (50°F), and sometimes even drop below freezing. The days are shorter too, which means there is less light overall.
In those conditions, seeds germinate more slowly, and sprouts grow at a much slower pace. Especially if they are left unprotected from the cold.
So when I’m growing lettuce seedlings outside, it usually takes six weeks instead of four. Or even eight, if I want them extra strong and well-established. And that extra time is fine too. If I start early enough, I still get plenty of harvest on time.
In the End, It’s Not About Speed
The key is to be realistic about the conditions you’re working with. Because in the end, what matters is what the plant becomes, and not how fast it gets there. I always prefer to wait two more weeks for a strong seedling that adjusts in an instant than rush one out in four – only to watch it struggle (or even die) later.