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' 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 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 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.

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

Friday, September 9, 2016

Good year for fruit on the Front Range

It is often said that spring freezes are the biggest danger to fruit growing. This year many areas of the Front Range were spared freezes at flowering resulting in generally good fruit set.

Another reason for heavy fruiting is that stored energy is high because many trees bore little fruit in 2015. A warm fall in 2014 didn't allow many trees to prepare for cold weather. Sudden subzero temperatures in early November 2014 following the warm fall caused freeze injury to a variety of plant tissues some affecting flower buds. That and usual spring freezes resulted in generally light crops in 2015. Not using energy on fruit last year left trees with ample stores to carry a large crop to harvest this year.

It will be a good year for gleaning to donate to food pantries but do check with landowners first.

This street-side apple in Louisville, Colorado also illustrates another point. Trees sited in heavily irrigated and fertilized lawns often respond with excessive vigor. They show lots of shoot growth and poor fruiting. This apple in an obviously sparsely irrigated and little fertilized area is bearing a nice crop as pictured in the close-up above.

The take away message is that mature fruit trees do better on less water and fertilizer than is applied to grow medium to high quality bluegrass lawns. A separate non-lawn site for growing fruit trees is a better growing situation for producing fruit rather than leaves.

Photo credit: Both apple tree photos credit Carl Wilson