Did I get you thinking?

It depends on your goals. If you are trying to fill your belly, the best crop to grow is potatoes. They produce more calories per area than any other crop. I’m not sure about you, but too much food energy is more of a concern in my kitchen.

What if your goal is nutrient density? What crop could you grow to have the most nutrient dense garden? In that case, greens are the way to grow. Greens are a rag-tag group of plants, united by the fact that we eat the plant leaves. That may seem ho-hum, but consider the toxic leaves of potatoes, peppers and tomatoes. Most plants would prefer that we don’t eat their main photosynthetic organ! We’ve evolved the greens over thousands of years to have mild and tender leaves. Now, let’s enjoy the thousands of years of work by our ancestors, and grow some greens.

As with most things about plants, we can understand their growth preferences and disease susceptibilities best if we group them by their families.

Brassicas

You could also call this group the cabbages. They are cool weather crops that like to be planted in May (either direct seeded or transplants). Since we are talking only about greens here, we want plants  that grow their leaves quickly and consistently so you can harvest the crop within 3-4 weeks. 

This group has many varieties of greens across several species. Mibuna, mizuna, tatsoi and komatsuna are excellent examples from this group: all offer an abundance of glossy green leaves that are mild and tender. If seeded in April in a tray and transplanted in May once hard frosts are over, you will be picking leaves by early June. Picking the fully expanded leaves but leaving the plant lets you harvest over several weeks. Once the weather gets really hot in July, these plants think about reproduction and quickly switch from making leaves to making flowers (you might say that the plant is hot and bothered!). When the plant hits its teenage moment depends on the variety. Some new hybrids of tatsoi are incredibly heat tolerant, buying you several extra weeks of leaves. Once the switch is flipped, the plant goes into seed forming mode and can either be pulled out to make room for something else or left to go to seed for collecting.

Mizuna
Komastuna

You may have grown kale (have you tried all the types- curly kale vs. green (e.g. Russian) kale?), but what about turnip and kohlrabi greens? These are dual-purpose crops. If you have tried cover-cropping in the fall, you can choose a seed mix with turnips. The turnips grow quietly all fall and in most winters, will sprout vivacious green leaves in spring. You won’t believe how joyful you will feel to amble around your garden picking tender leaves in April and early May. 

Be wary and avoid overly waterlogged soil or low sites that are prone to spring flooding, as this group will be more likely to rot in those conditions. 

With this abundance of benefits, there are some drawbacks. We aren’t the only ones who find these leaves delicious! In fact, there are so many widespread insects that attack these leaves that the best protection method is to use a row cover. These need to be used from the moment you put your plants in the soil, either as a floating row cover or using hoops. This will keep the Swede midge (a tiny fly whose larvae destroy the growing point) and cabbage looper moth off your plants.

One major pest emerges from the soil in May, and will not be stopped by a row cover: flea beetles. These pests eat holes in the very leaves you are planning on eating! When they have high populations, they can cause a frustrating level of damage. Spraying the leaves with any home-gardener approved potion isn’t really an option because you were planning on eating those leaves. Using transplants in this case can really help. Putting plants at the four-leaf stage into the ground can really give them an advantage to outgrow the damage from the flea beetles.

Chenopods

Botanical family names are funny; this group is also known as the goosefoots. Completely not looking like goose feet, spinach, chard and beet greens are in this group. They are also cool weather crops preferring to be planted in cool soil (10-15°C) and the plants have some frost tolerance. Chard comes in an assortment of exciting colours. Chard and beets are the same species (chard is just leafy and beets are rooty), but the greens do have different flavours. 

The leaves are tender and this means insects feasting on the leaves. Leaf miner is a major pest, but these can be controlled by ripping out the affected leaves and burying or throwing in the garbage. Simply dropping the leaves on the soil to decompose (as gardeners are fond of doing) will allow the eggs to hatch and start another round of infestation. 

Swiss Chard

Cercospora can be a problem on chard and beets. It’s a fungus that causes lesions on the leaf. That’s not really a problem when they are small, but the lesions will gradually cover the entire leaf, turning it brown and crispy. Difficult to control due to the number of wild plants that host the fungus, consistent harvesting of leaves is the best option to limit the fungus. It gives you a license for lots of baby leaves instead of waiting for bigger ones, if you find this in your garden.

Downy mildew in spinach can be a problem in cool, wet springs. Leaves have diffuse yellow spots above and fuzzy purple beneath. It can cause total loss. The best option is to select varieties listed as downy mildew resistant, trying to pick varieties listing resistant to the most strains of downy mildew.

Plant Nutrition

If you are a bit lost about what nutrients to add to your soil, then growing greens will be refreshingly simple. Leaves are the crop and plants grow more leaves if their nitrogen levels are optimal. If you haven’t been amending your soil with anything lately, grab a bag of any soil amendment at your local nursery and look at the analysis on the bag. Composted manure is a great source of nitrogen. Organic amendments are also critical for adding organic matter to soil, which is helpful for storing water in dry spells (and don’t we know how common those are now!).

If you are really serious about growing greens, planting family members from both the Brassicas and Chenopods is best since they suffer from different diseases and pests. For example, in years with bad downy mildew on the Chenopods, you hopefully will still have some Brassicas to harvest.

Two Other Groups to Consider

  • Perennial Greens – Flower gardeners know that perennials are less work once established than annuals. The same goes for food plants, plus the added benefits of leaving the soil undisturbed. Sorrel and Good King Henry are two green workhorses. Both sprout soft leaves early in spring. Harvesting the leaves for a month with continual re-sprouting of leaves does not seem to slow the plants down. Once the weather turns hot, they send up flower stalks and the leaves become tough. Sorrel can reward you with a fall harvest as well. It has a pleasantly acidic taste due to oxalic acid, and shouldn’t be eaten in large quantities due to this acid. Its flavour acts like lemon juice and it completely breaks down when cooking, making it perfect in soups and sauces. Good King Henry is sturdier (it’s a Chenopod too) but very mild. It’s very early, making slightly tougher leaves palatable when the rest of the garden is barren.
  • Weeds that are in your garden –When all else fails, you likely have some greens in your garden growing among the plants. Lambsquarters is a non-native plant thought to have been brought by the European settlers to eat as a green. It is related to spinach and grows vigorously in spring. Lambsquarters is a summer annual, germinating when the soil warms in May. Being a weed, it excels at scavenging nutrients in the soil (no need for any amendments!). When only a few weeks old and under 20 cm tall, it is tender and tasty! I was skeptical too, but the second  year of no spinach harvest (due to downy mildew and drought), I tried it and now look forward to it.
    Pigweeds are also edible and related to amaranth. We have a couple of types of pigweed in Ontario, but the most common in your garden are likely redroot pigweed and green pigweed. Green pigweed has shiny leaves compared to the hairy leaves of redroot pigweed. You’ll see both just after lambsquarters emerges.

If you see these weeds and they aren’t harming your plants, you can let them grow for a few weeks to 10-20 cm and harvest. They won’t have made seeds by then, so there is no harm. It’s the most rewarding weed pulling that you can imagine. Just make sure that you properly identify the weeds before consuming them.

As you can see, there are many greens that grow quickly and provide a power packed nutritional punch that can be grown starting in late spring when nothing much else is even close to harvest. No need to keep them strictly to the veggie bed either. Rainbow Swiss Chard looks very attractive growing amongst your perennials. Or stick some spinach in a spot that is normally reserved for a flowering annual. Once the weather is warm enough for the flowers, the spinach will be close to finished for the season anyway. Why not give some of these a try this summer.