Pricking out Lettuces

In horticulture lingo, the phrase “pricking out” is not just something Beevis and Butthead would chortle over, it  means “to pot up tiny sprouted seedlings into a slightly larger container”  It’s different from the horticulture term “to transplant,” in that the latter generally means to plant something from a container into the ground. 

I sowed four different lettuces on September 24 (two varieties per flat).  Each flat holds eight 6-packs.

I  generally sow more seeds than are necessary, because seeds are cheap, and re-sowing seeds that don't sprout can set you back a couple of sometimes crucial weeks.  If all goes well, and germination is good, that means that I’ve got too many of any one thing, and I need to separate the m and give them more space.

As I was teaching my prick out method to my fine assistant, Christopher, he asked me the obvious question, “Why can’t we just transplant these babies directly into the ground?  Why do we need this interim step, which will take a lot longer?”  Christopher’s always asking questions when he’s not belting out a song that he thinks summarizes what I’ve just taught him.  The tune he chose after this tutorial was Lionel Richie’s “Once, Twice, Three Times a Lady,” (you’ll see why at the end).

I told him to shut up and get his hands dirty (not really).  Rather, I patiently explained that the babies were way too little to put out in the cruel, wet, rainy world right now, and that even the littlest earwig could take it down with one munch.  However, since the tiny lettuces were too crowded in their little cells, they would need more room to grow before they were transplanted out into the garden proper to fend for themselves. 

Here’s our technique:

We pop the cell out of the tray 6-pack.  These little lettuces were sown almost 3 weeks ago.  This variety is called “Oakleaf.”  Wonderfully tasty.  There seem to be about 10 babies jammed together here.  We start to separate them by pulling apart the root ball.  Don’t try to separate by holding the too-tender tops.

We’ll discard any who lose their roots during the separation or are too small.  When we have a good sized baby separated with a decent root system, it’ll look like this:

Then we fill our nursery pot up to the top with good potting soil, and poke a hole in it with a finger.  We use “rose pots”, which are 2-1/4” wide at the top and 3” deep.  You can fit 49 rose pots into a square nursery flat.

We then gently place the seedling into the hole and backfill it WITHOUT pressing too much.  The new rootzone will need air just as much as it needs soil, water, and nutrients.  To firm it, we tap the bottom of the pot on the side of our soil tray to settle the contents.  We pay close attention to the height of the seedling above or below the soil line.  Ideal placement for lettuces is to plant them somewhat deeper than they were in the 6-pack cell.  Here is a perfect example:

And here is an almost finished tray:

Once the tray is finished, we immediately water them.  This is the part where I really harp on my apprentices to water them in well.  “Three times a charm,” I say.  It takes a while for the peat moss in the mix to absorb the water you’re pouring on them, and once or twice just isn’t a sufficient amount to do the trick.  The most critical time in the life of plants is whenever they are transplanted. I always water three times:  Once, let it drain, 5 minutes later another watering, then water again.

If this were a hot day, we would keep these in the shade for a day or two to help them recover.  But since it’s nice and cool right now, they’ll be perfectly happy in our giant hoophouse for another two or three weeks, when they will be ready for the big bad world.

Comments

[Denise Rugato]

This is such a great website. So much helpful information. Thank you for the info on lettuce!

[Lana Bryan]

Congratulations on the Martha Stewart showing! Very fun to see you and Chef Kinch in the video. Pricking up lettuce! Thanks for that! So fun to learn new garden terminology.

[Gary Millwood]

Cynthia, How much I would enjoy participating in your gardening and self-sufficiency workshops! Problem is I am in Kentucky and distance is a problem. I do gleen tidbits of helpful information from your blog I must say, I know of no other program which offers so many helpful and interesting hands on experiences for new or experienced gardeners.
Thanks for sharing your Newsletter with me. I always enjoy reading it!

[Love Apple Farm]

Luigi: I have yet to find a good source in the North Bay. I always like Sunland Garden Products based in Corralitos (South Bay, California). They will deliver in bulk, but I don't know how much you need. If you need less than a couple of yards, consider purchasing planting compost by the bag. I don't recommend compost that has as its main ingredient something called "redwood forest product," as that is too high in tannins. Check the ingredient label. And finally, there is no substitute for your own good home-made compost. Consider coming down and taking my Compost & Vermiculture class on April 7.

[Luigi DeMartini]

Cynthia, I have been growing about 18 heirloom tomato plants a year. I have been using what seems to be a strong manure planting mix. There seems to be too much nitrogen and I'm looking for a good organic compost. Can you give me any information - I am in
Marin County.

[Genna]

i love your posts about lettuce. I have never grown lettuce before but I lived on a farm once and got to taste the real difference in fresh lettuces and herbs, especilly cilantro. Now i have all the info I need to get going on it. Beautiful one stop shop blog site!

[Cynthia]

Annette, thanks for the great questions. You can sow seed in flats all throughout the year. You can also prick those out all year long and then transplant those out to the garden in your mild winter zone (like mine). If a frost is forecast, you'll have to cover up the lettuce bed with a frost blanket. We'll have a post about frost blankets within the next few weeks.

The only thing that is tricky about lettuce sowing is that it is hard to get it to germinate when you sow it directly in a garden bed in the hottest part of the year. Lettuce doesn't germinate well when it's exposed to temperatures above 75 degrees.

Also, lettuce will be hard to sprout out in a garden bed if it's colder than, say, 40 degrees at night.

So best to start lettuce seeds in flat indoors during the extremes of the year: either too hot or too cold. Otherwise, you can get away with directly sowing it in a bed, and then thinning as it sprouts and gets too crowded. The thinnings are delicious in salads, or just eat them as you thin.

[Annette Truong]

Great article on growing better lettuce! I never had success with lettuce before, but I usually tried to direct-sow it outside. I'll try these steps. Is there a time of year it's too late to seed lettuce inside / prick out / translpant outside? I'm in California zone 9b (San Jose).