Starting lettuce seedlings

9 lettuce after 4 weeks

Lettuce ready for planting outside after 4 weeks.

I started greens like lettuce, arugula, bok choy and spinach seeds on Jan 18, 2022. That is really early but I want to get them in the greenhouse and cold frame early. These steps would be the same for doing many other crops like chard, cabbage, kale, tomatoes only the seed starting dates will change . Many smaller seeds can be started this way.

seed germination tray

To start seeds I use a germination tray called a ‘20 row seed tray’ (google it to see where you can purchase these online). I use this style of germination trays for smaller seeds that I want to start inside and under lights for a head start in my garden. I cut the trays up into smaller sections but it’s not necessary. Seeds will germinate much faster in these germination trays. If you germinate seeds directly into a bigger pot or a pony pack, it will take much longer. If you want to read about how I plant the seeds in these germination trays go here.

This post is about the steps I do after I’ve germinated the seeds and how I transplant seedlings into pony packs.

2 wash pots

Wash your pony packs (4 pack or 6 pack) if you are reusing them in bleach and water (I don’t measure just a short pour in a sink full of water to disinfect them. I don’t scrub them-just dunk them in the bleach water and then rinse them in clean water (like bartenders) and let them dry. If they are new pots, you can skip this step.

1 dampen seed soil mix

1a Batch 64-Moonshine

Dampen the seed starting mix. If you don’t, the soil will not be damp enough and the seedling could die if it drys out. You want your soil damp but not dripping. I like “Moonshine” soil mix which has many organic nutrients and mycorrhizal in it which gets the seedlings off to a good start. You can buy it at Agua Fria Nursery here in Santa Fe or on Amazon. I use Moonshine for both starting seeds and when transplanting up to bigger pots.

3 clean pots and seedlings

Here the cleaned pots are next to the germination tray ready to transplant. I always keep my packs from previous flower packs until they fall apart. Put seed soil mix in the pony pots. Don’t forget to put some tape on the pony packs to write down which crops are in each pot. It’s also good to keep a written record as well.

5 holes is soil

Put holes in pony packs. I used a pen to make holes. I will put one seedling in each hole.

5 widen holes for bigger roots

Use your finger to widen hole if roots need more room-do not force them in a hole instead make the hole bigger.

handle seedlings by top not the stem

Handling seedling gently by the top leaves not the stem which could get damaged if you squeeze too hard. Put the seedling deep in the hole.The stem should be buried and only the leaves are just above the soil. Tamp down the soil and add a little more soil if needed but do not cover the leaves where new leaves emerge, only the stem. Water them with seaweed and SuperThrive or Vitamin B-12 (for plants not humans)

7 handle seedlings by top not the stem

These seedlings were transplanted 2 weeks later on Feb 3, 2022. One seedling plant per pot section. Don’t over crowd. If you grow this way, you will get bigger plants because they don’t have to compete with other baby plants which are many times really crowded in the packs and root bound. Grow cool hardy greens.

9 lettuce after 4 weeks

Above are the seedlings on Feb 17th. They are ready to plant in the greenhouse and cold frame. It’s still a little too cold at nite (low 20’s) so I will wait a couple of days till the night temperatures are in the high 20’s degrees or higher before planting. I’m a bit of a gambler when trying to plant early as a severe cold night can kill them even in an unheated green house like I have. But I’ve done this before this early and cold-hardy greens can usually tolerate cold temperatures with some help. My goal is to get lettuce big enough to eat by mid-March instead of just starting them. But you can wait till March to start them as well but you want to harvest them before it get hot and they bolt (form seed heads) and get bitter. Most people wait too late to plant while I tend to plant really early which may or may not survive depending on how cold it gets.

Since I am sneaking them so early, they will definitely need winter weight row cover over them every night even in the green house or cold frame. In fact to start, I may put 2 winter weight row covers on them at night. Do not use a bed sheet-it doesn’t offer any protection while row cover will offer 6-8 degrees protection. One winter weight row cover (.90+) will protect down to 24°F and if you see it will be colder, go ahead and throw another row cover on them.  Flip the cover(s) off in the day time and flip back on the plants at night.  As it get warmer above 24°F at night you won’t need 2 row covers. The whole process from planting seeds to transplanting takes about 4 weeks using this method and supplies. Then they grow another 4 weeks in the greenhouse and cold frame and I will start to harvest them. I should start picking lettuce in about another month or sooner. Woo! Hoo!

I also have a video here recording ALL the steps of transplanting.  I made a few mistakes in the video. I said I was planting bok choy but actually I was planting arugula. The seeds were planted Jan 18 and they were transplanted on Feb 2 out of the germination trays into the pony packs in this video. This was my first indoor video which was harder to film than outdoors but you will see the actual steps in progress.

Seed Heating Mats for Starting Seeds Indoors

I did a little experiment. I started my lettuce bowl, putting seeds on the ‘bowl’ and lightly covering with sand. I didn’t have enough room to put the whole bowl on my seed heating mat (I’ve ordered another one) so I put half ON my mat and half OFF the mat as in the picture. The heat comes from the bottom. The temperature of half ON the heat mat was 77°F and the half OFF the mat was much cooler at  70°F. The half on the mat germinated in 3 days while the half off the mat had only a few seeds germinate. Amazing how the temperature affects the germination rate. Lesson here? If you plan to start seeds indoors, get a seed heating mat. Next: Review of my Seed Starting Class last Saturday.