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

Environmental matters

On a garden tour this weekend I saw tomatoes 4 feet tall with fruit already set. The gardener said she got an early start and used water walls that were lifted off the plants a week ago. Quite a bit different than the June 1st planted plants I have that are 15 inches tall and just starting to flower. Temperature modification for an early start makes a big difference.

Speaking of temperature, both of our plants will be affected by tonight's low that is supposed to be in the forties Fahrenheit. It's always hard to believe that we could have temperatures this cool only a day following a 95 degree day that tied a record. Tomatoes will be stunted for a few days because the nighttime temperature is below the desirable nighttime low of 50 degrees F for tomatoes. This stunting increases the days needed to grow fruit to maturity. This is typical in high altitude areas in the summer and makes tomato growing difficult.

On another subject, the effects of the hail discussed last time continue. The leaves of all types of plants are taking on a faded appearance from the hail nicks scarring the leaves. Plants look similar to when they are in need of water. Check soil carefully before resuming irrigation and if wet, don't water. Plants also may have yellowed lower leaves from roots that shut down due to the excessive rain that came with the hail. Adding more water too early will only compound the hail damage.

It can't be stressed enough to dig down and check soil moisture in the root zone before watering anytime but particularly following heavy rains.

Photo credit: Plant four days after hailstorm - Carl Wilson

Hail - Nature's pruning

Widespread hailstorms and rain struck the Front Range Colorado area the evening of June 6 from south Denver to Parker and on south to Colorado Springs. Hail sizes ranged from rice grain to one inch sized and even higher. Copious amounts of rain accompanied the storms. In southwest Denver, my garden received 2 inches of rain and rice grain size hail.

The most important action the day after is to stand outside the garden for a post-event look. Check your raingauge and asses the size of the hailstones; pea-sized hail or less is generally not a big problem for plants. Avoid stepping into gardens because wet soil compacts easily. Turn off automatic irrigation systems. Then go away and wait for soil to dry out.

After a few days to a week, pick up detached branches and leaves. Damage to vegetables often looks worse than it really is. These plants are annuals and respond quickly to pruning. When soil dries and it's time to water again, use a low-strength liquid fertilizer to stimulate new growth. Vegetables that are newly established and reduced to sticks may have to be replaced while transplants are still available. It's also early enough to reseed many vegetables. The plants pictured here will recover nicely without replacement.

Patience and waiting for recovery and new growth are the best actions to take following hail events.

Photo credit:  Hail at base of raspberries with set fruit. Hail damage to summer squash and tomato. All credit Carl Wilson