Starting garden vegetables from seed can be intimidating, especially for a novice gardener. But when starting any seed, it is essential to ask three questions.
- During what season should this crop be planted?
- Should this seed be direct sown, or should I start it indoors?
- How many seeds do I sow?
In this particular article, we will be discussing the best methods for planting, growing, and harvesting lettuce.
When to Plant Lettuce
Lettuce is a cool-weather vegetable. This means that it should be planted in early spring or early fall as it is sensitive to heat. Most lettuce seed varieties only need soil temperatures of sixty degrees Fahrenheit to germinate properly but will start to bolt when daytime temperatures are consistently above seventy-five degrees Fahrenheit. There are varieties such as Merkurion or Medimo that are bred for bolt resistance, but in general, lettuce and most leafy greens do better in cooler spring and fall temperatures.
You will know it’s time to spring plant as soon as nighttime temperatures are regularly at or above 40 degrees. When that happens, plant quickly so you don’t miss your window. Once your plants begin to bolt, or the leaves taste bitter, it is too hot. Pull them and wait to replant in the fall once daytime temperatures have cooled again and grow until frost.
How to Plant Lettuce
There are two methods when sowing seeds. The first is direct sowing. This means you plant the seeds where you intend them to grow all season long (no transplanting required). The second is to start seeds indoors and then transplant them outdoors once they reach a certain level of maturity.
While lettuce can be started indoors and transplants reasonably well, it needs quite a bit of light to germinate and mature, often getting ‘leggy’ without the proper amount of light. Adolescent starts can also be very tender and their root systems are not very sturdy. So, for these reasons, lettuce does best when direct sown.
Lettuce seeds are tiny and delicate and tend to “travel” (move with the elements) when planted outdoors, but they cannot be buried too deep because they are so small and require light to germinate.
It is easiest and most efficient to sow your seeds by roughing up the earth where you wish to plant them, scatter your seeds over the worked area (don’t be too heavy-handed), and then very lightly cover the area with a light dusting of topsoil or peat moss so that light can still reach the seeds. Don’t bury them; this dusting is just to hold the seeds in place until germination and shouldn’t be any thicker than the seeds themselves.
Once seeds are sown, water well and keep the area moist until you see signs of germination, then gradually reduce to a regular watering schedule. Depending on how well your seeds germinate, you may need to thin your lettuce patch some. Most varieties of lettuce have a germination period of seven to ten days. Your seed packaging should tell you the expected spread of each plant and germination rate. Your seeds will do best planted somewhere in full to mostly-full sun with well-drained rich soil.
Choosing Lettuce Varieties to Grow
There are a few things to consider when deciding which variety of lettuce to grow.
Leaf lettuces can be harvested all at once in a bunch or leaf by leaf producing for their entire season. These are ones you see in the grocery store often bagged and sold as “baby lettuce” or “spring mix .” Some of the most popular leaf varieties are Royal Oakleaf, Green Salad Bowl, or Two Star.
Head lettuces are ones you are probably most used to seeing; Romaine or Iceberg are the most common. But head lettuces can be far more exciting than your wedge salad standards—varieties like Cimmaron, Dragoon, and Coastal Star all jazz up the head lettuce corner.
If you want to grow head lettuce, you will likely need more space and more seed as the harvest ratio is one to one, meaning one head of lettuce for every start/seed. Whereas with leaf lettuce, you can get continued cuttings or harvests from the same plant, meaning you need less space and fewer seeds for the same yield.
It is important to note that head lettuces, when picked at peak maturity, also tend to store just a little longer than cut leaf lettuce does, but we will get into that a little later when we discuss harvesting and storing. Choose a variety that best suits your needs and space and then sow accordingly.
How to Care for Lettuce Plants
Caring for your lettuce once it has sprouted isn’t too complicated. For crisp but tender leaves, be sure to maintain a strict watering schedule. Water is needed if your leaves start to look a little thin or begin to droop.
Lettuce has a such short season that it usually doesn’t require any complicated or advanced fertilization methods. A standard all-purpose vegetable fertilizer will do just fine.
When it comes to pests, the ones you will need to be most wary of are aphids and leaf miners. Aphids are small light green or sometimes black winged insects about the size of a pencil point. They secret a stick substance and often attach themselves to the undersides of the leaves deep within the plant near the crown.
Leaf miners are a flying insect that are rarely seen, so you don’t realize they are a problem until their larva, laid within the plant leaf, hatches and begins to develop. The larva eats out the innermost parts of the leaf, leaving a bubble between the outer edges of the leaf hence the term “miner.”
Both pests should be treated immediately upon proper identification. Neem oil is a great place to start for proper treatment; just be sure to read the application guide in its entirety to be sure it is applied safely and effectively.
How To Harvest and Store Lettuce
When harvesting your lettuce, it is best to do so first thing in the morning when temperatures are cool and leaves are firmest and less likely to be stressed by cutting. You may harvest your lettuce leaves in the “baby” stage for the most tender and sweetest leaves.
Using a pair of herb snips of clean, sharp scissors, cut leaves one at a time directly at the base. Keep in mind, though, if you want your lettuce to continue to mature and produce, it will still need a good portion of its leaves to remain viable, so do not cut more than 40% of the leaves from any one plant at a time.
If you want to wait for your heads to fully form before harvesting, again, just make sure you are doing it during the cool morning hours and cut the head from the root directly at the base. It is important to note that fully mature lettuce (head or leaf) will always store longer than tender baby greens.
Whether you are storing leaf lettuce or heads of lettuce, they will keep longest if you wrap them in a slightly damp paper towel or linen towel and refrigerate. Then only wash what you plan on using when you plan on using it. Washing immediately and then storing leaves excess moisture causing rot or limp leaves.
Overall, lettuce is an excellent addition to any vegetable garden and is one of the first and the last vegetables of the season that we get to enjoy. Though it can be a learning curve, it is worth the effort, and following these tips and tricks, you should be a lettuce pro, enjoying salads straight from the garden in no time flat!