Asian Greens

If you haven't investigated the world of Asian greens, they will surprise with their versatility and tastiness. The striking appearance of many are a welcome addition to the garden. Cool season types such as those mentioned here can be planted now.

'Brisk Green' pak choi

Pak choi (a.k.a. pac choi, bok choy, Chinese celery cabbage, Chinese white cabbage) Brassica rapa var chinensis, is generally a cool season vegetable though improved heat tolerance has been bred into some. The green leaf stalk types like 'Shanghai' and particularly the F1 varieties 'Mei Qing' and 'Brisk Green' with more heat and bolt resistance are good candidates for us. They can be sown in place and the young greens cut in 20 days while thinned plants left to mature in 45 or 50 days depending on variety. Pak choi may be eaten raw, stir fried, grilled, steamed or added to soups.

Pak choi 'Brisk Green' bolting mid-June

Seed of pak choi is available from general seed companies such as Johnny's, Nichol's Garden Nursery and Territorial as well as specialty Asian vegetable seed suppliers like Kitazawa Seeds. Sow directly in the garden in April and again in early July for a fall crop. As with other cabbage family members, flea beetles and cabbage caterpillars can be troublesome. Try floating row cover fabric to screen them out.

'Indian Red Giant' mustard

Asian mustards, Brassica juncea, are fast growing cool season crops. A particular beauty is 'Indian Red Giant' mustard, 40 days to maturity or half that time for baby salad greens. This maroon leafed plant forms a welcome addition to lettuce or spinach mesclun mixes and can also be used as wilted greens and in soups and other cooked dishes. The peppery flavor and texture of the leaves are very different than American mustards. Originally thought to come from India, it is popular in many places in Asia. Seed can be obtained from local Broomfield based Botanical Interests.

Photo credit: All story photos credit Carl Wilson

Bees to pollinate your Vegetables and Fruits

Digger bee coated with pollen - Whitney Cranshaw

Devoting valuable growing space to flowers to nurture bee pollinators may seem like a waste of time to vegetable and fruit growers. Perhaps it's time to rethink and plant some low-care perennial flowers for bees.

Pollinators have been in decline with increasing urbanization and the mysterious honey bee colony collapse disorder. We need bees to pollinate our food. Vegetable growers need to be concerned about pollinators for their vine crops: cucumbers, melons, squash and pumpkins. Fruit growers are even more dependent on pollinators for brambles, strawberries and tree fruits.

Sweat bee and honey bee - Whitney Cranshaw

Although you may automatically think of honey bees, don't sell bumble bees and solitary bees short when it comes to pollination. There are a whole variety of native solitary bees to consider.

Some of the better low water and low care perennials to consider growing for bees are:

• Sunflower (Helianthus sp. but not pollen-free florist types or fancy doubles)
• Catmint (Nepeta - extend flowering by cutting back after first flowering for a second flush of bloom)
• Beardtongue (Penstemon sp. including Rocky Mountain penstemon, P. strictus)
• Russian sage (Perovskia atriplicifolia)
• Mint (Mentha sp.)
• Purple coneflower (Echinacea purpurea)
• Blue mist spirea (Caryopteris x clandonensis)
• Lavender (Lavandula angustifolia)
• Silverheels horehound (Marrubium rotundifolium)

Also consider succession of bloom over the growing season. Don't know when perennials bloom? Click to find a helpful publication from Utah State University Extension complete with flower bloom time chart that is highly applicable to us in Colorado:  Gardening for Native Bees in Utah and Beyond.

Transplant Seeding

The time is near to start seed if you're planning to grow transplants of tomato family plants. Count backwards from your desired date to plant out your transplants to determine a seeding date. Beginning gardeners often start plants too early and end up with overly large plants of declining quality that have outgrown their pots.

Tomatoes require 5 to 7 weeks to grow a transplant. Peppers and eggplants require slightly longer, perhaps 7 to 8 weeks. Remember to allow a week longer if growing on a windowsill or under low light conditions. In a greenhouse with good light and temperature control, a shorter growing time is needed. If planning to transplant out the last week of May in Denver, the first or second week of April is a good target date for seeding.

Other typical transplants, primarily vine crops, should be seeded later. Squash, cucumber and melons require only 2 or 3 weeks to produce the small-sized transplant needed. The root system on large vines does not transplant well on these crops.

Just a note if you haven't already acquired seed of tomatoes. Tomato Fest out of California is a good source of heirloom tomato seeds that is not well known in Colorado. This is my source for seed of 'Azoychka', a yellow tomato that is well adapted to our area as I've written in previous posts.

'Azoychka' (see photo)  produces 3 inch tomatoes with good acid to sugar balance and nice citrusy flavor notes for those who like yellow tomatoes. It is a 70 day indeterminate type that comes from Russia. This variety rated in the top ten heirlooms sold by Tomato Fest and deserves a try in your Front Range garden.

Photo credit: Planting seed to grow transplants and 'Azoychka' tomato, both Carl Wilson

Lettuce got variety

In the centuries since the early Egyptians and then Greeks and Romans first cultivated and selected lettuce, a wonderland of forms and colors have been developed. Now that Front Range soil temperatures have generally reached 40 degrees F consistently, it's time to seed lettuce and other hardy cool season vegetables.

The mesclun mix pictured above left shows some of the variety to be found in lettuce and many mixes are now on seed racks and in catalogs. Even so there is something to be said for growing a single variety both in the way it looks in the garden and in the salad bowl. Here are a few you may want to try. All photos are of lettuce growing successfully in Denver.

'Lollo Rossa' is an Italian heritage lettuce noted for it's frilly leaves. This looseleaf lettuce is ready in as little as 30 days. Pictured is 'Dark Lolla Rossa' which is a garden showstopper when paired with a light green oakleaf lettuce. Oakleaf is another 30 to 40 day type that has been cultivated in America since the 1800's. Both red and green oakleaf varieties can be found.

Another heirloom lettuce cultivated by Thomas Jefferson at Monticello as early as 1809 is 'Tennis Ball'. It's a butterhead type that requires 50 days to maturity.

The Mennonites brought 'Speckles' lettuce to America from Germany and Holland 200 years ago. Another butterhead type, this one matures in  50 days.

If you want to try a head lettuce, 'Pablo' is a Batavian loosehead lettuce with tender leaves that grows in 68 days. It's open pollinated and you can save seeds if so inclined.

Although lettuce is a hardy annual, seed or transplant soon so it can complete growth before hot weather. Hot temperatures cause it to flower ruining the quality of the leaves.

Photo credit: Mesclun mix, 'Dark Lollo Rossa' and oakleaf lettuce, 'Tennis Ball' lettuce, 'Speckles' lettuce, 'Pablo' lettuce, all credit Carl Wilson.

Raspberry pruning time

It's time to finish pruning last year's raspberry canes before new growth begins. The fall types that bear in August on first year canes are pruned to the ground every year in late winter.

Based on information from Cornell University, the best time to prune is from December through early March. Before December, the plant is still moving energy from plant leaves to the crown and pruning canes removes valuable carbohydrates. After early March, carbohydrates have already moved from the crown to buds that may be removed in pruning.

Prune canes as close to the ground as possible so that buds break from below the soil surface. If you leave a stub, buds break on the stub and resulting canes are poorly anchored and subject to breaking in winds. In the photo right, two canes near the head of the pruning shears have been correctly pruned at ground level. The four inch stub at the right of the photo should be pruned again closer to the ground.

Gather all pruned canes, rake fallen leaves and remove all plant materials from the site. This eliminates overwintering aphids and other insect and disease organisms.

While the single crop produced by the fall bearing type raspberries is smaller than traditional summer bearing types that bear fruit over two years, management is much easier. Rather than pruning the two year canes of summer types after bearing in late summer from among new, one year canes, all canes of fall types are easily pruned to the ground in late winter. Eliminating detailed pruning is only one advantage of fall types. Also eliminated are cane thinning, support and tying, cold injury of buds on overwintering canes, overwintering insects and damage from rabbits or voles. For all these reasons the fall bearing type raspberries are recommended.

For more information on growing raspberries and other small fruit, attend one of my classes (see schedule right column).

Photo credit: Pruned raspberry canes, Closeup of pruned canes, Disposal of raspberry prunings - All credit Carl Wilson

Tomato taste information for seed ordering

With all those seed catalogs arriving, lots of tomato varieties look tempting. Which ones taste the best?

A taste test last season in Boulder, Colorado identified some favorite tomatoes. Among 40 salad tomatoes including low-rated 'Celebrity' and 'Stupice', 'Siberian' came out on top with 'Carmello' and 'Cosmonaut Volkov' close behind. Those were followed by 'Jetsetter', 'Green Zebra', 'Early Girl' and 'Valencia' that formed a respectable second tier.

For beefsteak types, the winners out of 23 compared were far and away 'Pineapple' and 'Amana Orange'. Those receiving respectable but far fewer votes were 'Paul Robeson', 'Cherokee Purple', 'Black Krim', 'Black Sea Man', 'Brandywine' and then 'Black from Tula'.

Thirty-one cherry types were taste tested with the winners 'Sungold' followed by 'Yellow Globe', 'Isis' and 'Green Doctors Frosted'. The second tier included 'Matt's Wild Cherry', 'Chiapas', 'Yellow Pear' and 'Green Doctors'. Respectable ratings were given to 'Wow', 'Sweet 100', 'Sunsugar' and 'Black Cherry'.

Eight paste tomatoes were in the test with 'Plum Zebra' winning by far. And yes, standards 'San Marzano' and 'Roma' were in the test but rated very low.

This test will tell you something about how a group of people rated the taste of tomatoes grown locally. It says nothing about how productive, how early, or how disease or crack resistant these varieties are to name a few things you might be looking for. Keep in mind your own production needs when choosing seed to plant.

Photo Credit: Tomato fruit in bowls - Carl Wilson