Wednesday, May 3, 2017

Determining tomato varieites

The pun in the title is meant to call attention to the growth habit of tomatoes as gardeners pick varieties for planting this month.

Determinate tomato growth ends in a flower while indeterminate types produce vegetative growth and flowers until frost. Of course there are some inbetweens. They are  known as semideterminate types but even that doesn't fully capture growth habits as some are sprawling and some short, upright plants.

Determinate 'Fantastico' F1 hybrid
grape tomato. All-America Selections.

What's the big deal about growth habit other than considering it in allocating garden space, planting distances and staking needs? A lot.

Last time I wrote about the narrow temperature range for pollination of flowers. Determinate types tend to produce flowers all at once and then not many additional ones as they top out. That is great if you want many tomatoes at one time for canning or marketing. It doesn't work out so well if the bulk of flower production occurs during a cold or hot period that is poor for pollination and results in few fruit.

The other consideration is fruit flavor. As Randy Gardner, tomato breeder at the Mountain Horticultural Crops Research station of North Carolina State University, has been noted as saying, the fruit of determinate types will never have the flavor of indeterminate types. They don't produce the ample amount of leaves to photosynthesize and supply fruit that indeterminate types do. He is the breeder of the "mountain" tomato series including 'Mountain Spring' and 'Mountain Merit'. Both are 70-some day to maturity types and are recommended for commercial growers in Colorado.

Mr. Gardner has also said in interviews that his varieties are bred for commercial producers but were adopted by home gardeners in the East when an outbreak of late blight widely took out plants a few years ago. We have little problem with late blight in the dry West, especially if you water at the soil level and keep foliage dry (no overhead sprinklers).

While Mr. Gardner and other plant breeders have bred more disease resistance into their hybrids than heirlooms have, that generally isn't a big reason for choosing varieties here unless you have a problem with TSWV or some other specific disease.

In general I recommend that home gardeners choose indeterminate types or at least a mix of indeterminate and determinate. Even if you want to grow tomatoes for paste you have the choice of indeterminate 'San Marzano' or newer, shorter-season indeterminate hybrids rather than determinate 'Roma'.

Know the growth habit of the variety you are planting as well as the days to maturity (80 days or less in Denver) before purchase.

Photo Credit: 'Fantastico' F1 tomato - All-America Selections

Saturday, April 22, 2017

Choosing tomato varieties


The Front Range has varied topography, elevations, location in relation to nearby mountains and microclimates. Every season is different as temperature and rainfall vary through the growing season. A tomato variety that performs well one year may not the next.

For example last season (2016) many people complained that they had few ripe tomatoes by late summer. Summer heat was likely to blame for poor pollination and fruit set. Denver had 44 days from June through August with temperatures over 85 degrees F, temperatures where blossom drop is likely. Greeley had 68 days.

Fortunately we had a fall with extended favorable temperatures so gardeners had time to ripen late-set fruit.

Not only temperatures too high to set flowers but also night temperatures too low are a factor. Our neighbors to the north in Cheyenne had 52 nights in the June to August 2016 period with temperatures under 55 degrees F, poor conditions for pollen viability and pollen tube growth to set flowers. Denver had 16 nights in the same period and Greeley 33.

While it's challenging to choose tomato varieties to grow in our Front Range conditions, the good news is that there are lots of varieties out there and more every year.

My recommendation is for short season varieties (80 days to maturity in Denver, 70 days or less in Cheyenne). Varieties with northern adaptation are also good candidates. These might include Russian heirlooms such as 'Azoycha', 'Aurora', 'Anna', 'Alaska', 'Paul Robeson', 'Black from Tula' or German 'Gardener's Delight' , 'Blondkopfchen' and 'Bloody Butcher'.

Also hybrids such as 'Northern Exposure', 'Juliet', 'Parks Whopper', 'Big Beef', 'Summer Girl' and 'Fourth of July'. New this year is an All America Selection winner 'Midnight Snack', a cherry type that is touted as an advance in flavor for purple types.

Hybrids from crossing heirlooms are also gaining popularity and include 'Brandy Boy,' 'Big Brandy', 'Genuwine' and 'Perfect Flame'.

I also recommend a mix of varieties including both heirlooms and hybrids. Chances are that if one doesn't perform well under this year's weather conditions, another will.

Photo credit: Windowsill tomato starts - Carl Wilson

Monday, April 3, 2017

Spring freezes and fruit trees

Peach bloom April 1, 2017
A recent look showed peaches in full bloom in Denver during a week in which night temperatures are expected to drop to the mid to low twenties F.

Spring freezes during bloom are the biggest concern for home fruit growers.

While a dry March had few cold nights, April is shaping up to have much more variable weather. This includes rain/snow storms followed by cold nights due to radiational cooling after storms pass and skies clear.

USDA Hardiness Zone 6 or better yet Zone 7 (Colorado's West Slope) are better areas to grow peaches than Zone 5 Denver. While there are Zone 5 peaches, many backyard growers don't hunt for and plant them.

Yellow Delicious apple
bloom April 1, 2017
Peaches aren't the only trees with blossoms out now. This Yellow Delicious apple tree is well on its way to having flowers out during this week's expected cold nights. Yellow Delicious is a medium chill apple (600 to 700 chilling hours), fireblight susceptible and not on my list of recommended varieties for the Front Range.

Honeycrisp is a medium to high chill apple (800 to 1000 chill hours) that is more fireblight resistant and on my recommended variety list. As you can see in the photo, it breaks bud later than Yellow Delicious.

Honeycrisp apple branch
March 30, 2017
What can you do with a tree in bloom when frost is expected? Homeowners with young (short) or dwarf trees can throw a plastic cover over them and use a heat source underneath. While there may be some heat in the ground to trap after a warm March, you will have to supplement as soils aren't that warm yet.

Lights with old-style incandescent bulbs or any bulbs that produce heat will work. Do be mindful of fire safety when using lights under covered trees and remove tarps the following morning to avoid overheating trees on sunny days.

See the CSU Extension Garden Note 722 "Frost Protection and Extending the Growing Season" section on Lights for Addtional Heat for a description of using plastic covers and Christmas lights for warmth. Does anyone have another favorite way to provide supplemental warmth under a covered fruit tree that they want to share?

Photo credit: All photos Carl Wilson

Monday, March 13, 2017

Fruit tree bloom could be early?

Apricot 'Sungold' Mar 11, 2017
This week's forecast calls for weather not just in the sixties, but reaching into the seventies and possibly even eighty degrees F by the coming weekend. If the warm weather we've been having causes early bloom of fruit trees, blossoms could be caught by freezes.

Apricots are notorious for early bloom. Pictured is Prunus armeniaca 'Sungold' at Denver Botanic Gardens that was in full bloom this past weekend. Apricots may only bear fruit one year out of five (?) here on average because blossoms get caught by freezes in late March and April. The good thing about apricots for a homeowner is that they make a handsome ornamental landscape tree even if there is no fruit crop.

'Sungold' apricot bloom closeup
The bigger concern is with our other fruit tree species that may start to break bud as chilling requirements are met and temperatures allow them to resume growth. They need moisture to do this as well.

Along with cold temperatures, moisture has been lacking so far this spring. Watering your fruit trees is likely a good idea on the Front Range if the current dry conditions continue. Thankfully, our mountain snowpack is now around 130% of normal so we have water to irrigate.

Photo credit: Both apricot photos Carl Wilson

Friday, January 27, 2017

New Vegetables for 2017

'Patio Choice Yellow' tomato
Got small spaces? 'Patio Choice Yellow' F1 tomato may be right for you.

An All-America Selections winner, this tomato is a compact, determinate plant growing only 15 to 18 inches tall. It's the perfect size for container growing on a balcony or other small space.

Vines can bear 100 fruit and begin bearing in only 65 days from sowing seed.  The 1 inch bright yellow fruit are mildly sweet with a touch of acid.

'Antares' F1 bulb fennel
Why not try something new in your garden this year? 'Antares' F1 fennel not only produces an edible bulb, it's fine textured fronds are very ornamental in the garden. You can grow the plant for its culinary seed and it is also a favorite food for swallowtail butterflies and other pollinators.

The bulbs are said to have an improved, almost sweet licorice-anise flavor as compared to other market varieties. It is also a week slower to bolt.

Fennel is a warm season vegetable that will grow bulbs 4 to 5 inches in diameter and foliage 24 inches tall. Grow in rows 6 inches apart with 24 inches between rows. The plant is ready to harvest 68 days from sowing seed or 58 days from transplanting. Plants can be grown in a container if desired.

Photo credit -  All-America Selections

Tuesday, October 4, 2016

Pumpkins for many purposes

Pumpkins grow in a south-
facing bed with strawberries
(Photo credit Carl Wilson)
Pumpkins, Cucurbita pepo, are easy to grow if you have room. A 10 to 15 foot vine spread is typical although there are a few bush type varieties (see Wee-B-Little below). Plant from transplants as soon as the weather is warm because they require 90 to 120 days to harvest.

In the photo a home entry walkway is bordered with a bed used to grow strawberries in early summer and pumpkins for fall. A few tulips come through in spring to add some color to this garden. Talk about making good use of garden space for many purposes!

You may want to grow pumpkins for one or many uses including decoration, cooking and baking. Fruit size may also be important to you. Know that there are pumpkins to fit most any requirement.

Baby Bear 
Baby Bear is a small, 3.5 to 5.5 inch pumpkin weighing in at 1.5 to 2 pounds. It is just the right size to use for decoration and sweet so it can be used for pie fillings.

Hijinks
Hijinks is slightly larger at 7.5 inch diameter and 7 to 9 pounds. It's blocky round shape makes it ideal for carving.

Cinderella's Carriage
The pink-red color of Cinderella's Carriage variety will fulfill the fairy-tale dreams of any child. Vines grow flat fruit up to 18 inches round and weighing up to 20 pounds.  The yellow flesh is mildly sweet and ideal for soups and baking.

Pepitas
Pepitas is a new 2016 twist in pumpkins with it's yellow-orange fruit striped with green. Twelve inch round fruit weigh in at about 12 pounds. The hulless seeds can be slow roasted for nutritious snacks and yellow flesh eaten or baked.

Wee-B-Little
Finally, if you have 6 to 8 feet of space try growing Wee-B-Little, a bush type. Fruit is 3.5 inch in diameter and skin a smooth, deep orange. It can be used for decoration, crafts and makes a tasty vegetable when baked as a mature winter squash.

All five varieties mentioned are All-America Selections winners that should grow well in the Intermountain West.

Photo credit - All-America Selections unless noted