Lettuce be friends - Growing & harvesting lettuce -Urban Farm and Kitchen

Upping your salad game. A guide to growing gorgeous lettuce heads and mixed greens

I'm dedicated my first gardening post to the humble salad. When you close your eyes, and picture a salad, what do you see? Is it a vinegary pasta salad? A creamy potato salad? An ambrosia salad? [Ok, side note, if you don't know what an Ambrosia Salad is, google it!... I can't even believe this thing is considered a salad!]

Generally, people think of salad a boring lettuce with some other veggies like cucumbers and tomatoes. Does anyone really crave this? I certainly do not.

But, salad can be so much more. Crisp butterhead lettuce with shaved Parmigiano Reggiano and aged balsamic vinaigrette. Grilled romaine hearts with an avocado lime dressing. Homegrown red-veined arugula and mustard greens with roasted peaches. The possibilities are really endless.

Growing conditions

When it comes to growing lettuce, nothing can be easier. Lettuce (and most other crops considered greens like arugula, kale, mustard, ...) are cool weather crops. They grow well in cooler temperatures of spring and fall (or winter if you're in California). This means that they tolerate cold (and even freezing) temperatures. I live in southern Ontario, Canada (Zone 6) and as such, can only start thinking about growing lettuce and other greens a few weeks before our last expected frost date around May 10.

Growing medium and planting techniques

Lettuce will happily grow in the ground, in raised beds, in containers and hydroponically. It's really quite versatile. I grow lettuce, arugula, baby mustard, baby kale, mixed greens in my backyard raised beds, containers and my new rain gutter wall. The important thing is to use the right type of growing medium for the respective style of planting.

Container grown lettuce requires a container-specific potting mix. You cannot use a top soil, or standard garden soil in a container because these soils will compact and not provide adequate drainage and aeration. You have to use a container-specific mix. Usually, this is a peat based or coconut coir based product and included compost, vermiculite/perlite, slow release fertilizer and other ingredients. You can also mix your potting mix (many variations and recipes available).

Raised bed grown lettuce (and in-ground grown lettuce) require rich, fertile and airy soil. My raised beds are filled with compost, peat moss, top soil. Every year I top it up with more compost or composted sheep manure. To read more about my raised beds, check out my blog post here.

Buying seedlings

Even though growing lettuce and greens from seed is quite easy, if you're a beginner, you can purchase seedlings from your local garden centers and nurseries. That's what I did when I first started. The advantage of buying seedlings is that someone else did all the work of seeding, watering, and nurturing the baby plant for you. The disadvantage is that varieties are generally limited. Follow the directions on the tag and you'll be eating homegrown lettuce in no time!

Growing from seed (direct seeding and starting indoors)

This is my preferred method. Seed suppliers have endless varieties and mixes to choose from. Head lettuce, loose leaf lettuce, spring greens, spicy greens, arugula, and so much more!

Some seeds are labeled as pelleted. This means that that each seed is coated in a substance (usually clay) that makes it easier to handle and plant. I find pelleted seeds germinate better than non pelleted seeds, but that could just be a coincidence. I did not conduct a scientific study to confirm my findings.

This year, I am growing several varieties of head lettuce:

Salanova (Johnny's Seeds)
Breen (Johnny's Seeds)
Freckles Lettuce (High Mowing Seeds)

I am also growing several varieties of "baby greens" or loose leaf salad mixes (think of those bags of arugula, spinach and mixed greens you can get in the store):

Arugula
Red Veined Dragon's Tongue Arugula
Red Mustard
Redbor and Tuscan kale
Bok Choy

The head lettuce varieties can be directly sown outdoors, but I prefer to start those indoors under lights. This gives me a head start on the growing season so when the soil is workable, I can harden off the seedlings and transplant them (hardening off is the process of slowly introducing seedlings that have been grown indoors to the outside elements. Start with 1 hour a day and increase exposure over the course of a week). This method also allows me to employ succession planting, whereby I can start seeds every couple of weeks and have a continuous supply of lettuce to harvest.

Common pests

Because lettuce is typically grown in the spring, pests are not too much of a problem. In my experience, pests that love to munch on my seedlings include slugs and pill bugs. As weather warms up, other pests start to show up. Pests differ from region to region so you'll need to do a little research. Here are some common ones that tend to like lettuce as much as we do:

Flea Beetles

A small, jumping beetle that is barely visible. They feast on foliage and leave small holes all over leaves. They are difficult to control organically and I have somewhat learned to live with them. However, there are recipes available online for concoctions that claim to control this pest. The best defense when your plants are still small seedlings trying to establish themselves is to use floating row covers or insect barrier.

Leaf Miner (affects certain types of greens like chard, arugula, beet greens)

Leaf miners are the larvae of insects (typically moths) that live between the membranes of leaves and feast on the tissue. They leave behind a distinctive trail on the leaf. They can be quite destructive. The best way to prevent them in the first place is to use floating row covers or insect barrier. You can also check the underside of affected crops and remove the tiny white egg clusters manually. My advice, after planting any leaf miner prone crops, cover them up with insect barrier.

Leaf miner damage on leaf. — Leaf miner damage

Leaf miner eggs on leaf. — Leaf miner damage

Aphids

Aphids are small sap-sucking insects and come in a variety of colors. You'll find them on may crops. If you see then, the best course of action is to use a hose and blast them off. Another great way to control aphids is to attract Lady Beetles (ladybugs) to your garden (you can also purchase dormant ladybugs and release them in the garden. This is also super fun if you have kids!). Ladybugs (and more so ladybug larvae) feast on aphids all day long!

Slugs and snails

For the organic gardener, there isn't much you can do to deter slugs and snails. Some people use beer traps, copper tape and other methods. In my case, I have found that making sure the soil is free of debris, removing dying foliage and general garden cleanliness helps. Beer traps tend to work really well! Just don't use the good stuff!

Pill bugs (Rollie Pollies)

Who didn't love playing with these bugs as a kid? You touch them and they curl into a hard-shelled ball. They tend to consume dying or decaying matter in the garden, but I have found them crawling between the leaves of my lettuce. One good way to control them is to use Diatomaceous earth also known as D.E., diatomite, or kieselgur. This is a naturally occurring substance (the fossilized remains of diatoms, a type of hard-shelled protist (a single celled organism). The powder consists of minuscule crystal-like structures that absorbs fats from the insect exoskeleton and leads to dehydration and eventual death of the pests. I prefer to use food grade DE and sprinkle it around my plants. You will need to re-apply after it rains.

Fertilizing

Honestly, I do not fertilize my lettuce or salad greens after they have been seeded or transplanted. I make sure that the soil or medium I am planting them in has been amended with good compost, manure and organic fertilizer. If you wish to feed your lettuce as it grows, you can use an organic liquid fertilizer like a fish emulsion with an NPK balance number suitable for whatever crop you're growing. However, since these crops tend to be quick growing from seed to harvest, the nutrients present in your soil/medium should be sufficient. This advice doesn't hold true for long season crops like tomatoes or peppers that typically require feeding throughout the season.

Harvesting

Baby leaf greens can be harvested as needed. They are cut and come again (as long as you don't cut off the main stem). Just snip leaves as needed and they will regrow.

Head lettuce is typically harvested once, when the head reaches the desired size. Take a sharp knife and run it along the soil line to detach the lettuce head from the root. Alternatively, you can easily remove outer leaves as needed while leaving the head the keep growing. I've done that before with Romaine lettuce and harvested outer leaves as needed.