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

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

Varieties Adapted to Front Range Colorado

Amy's Apricot tomato

Cherry tomatoes are convenient for many people and golden cherry tomatoes have been of interest. Sun Gold is one that seems to do well in Denver and has become popular.

This year I tried another heirloom, Amy's Apricot, that did equally as well and has excellent flavor. An indeterminate type like Sun Gold, the only concern for some may be that Amy's Apricot is is 10 days later at 74 days versus Sun Gold at 55 to 65 days. Tomatofest.com carries Amy's Apricot seed.

Caroline fall bearing raspberry

Switching to small fruit, your fall bearing raspberries should be yielding well by now. If you are still growing Heritage red raspberry, consider switching to an earlier bearing variety when you pull out plants (generally necessary due to virus buildup after 10 years or so).

Newer fall raspberry varieties such as Caroline, Jaclyn and Autumn Britten bear fruit 2 weeks earlier. Late bearing Heritage has always been problematic with coming into bearing when frost danger may threaten in mid to late September.

Fall bearing raspberries are generally recommended in Colorado because they bear on first year canes; you don't need to worry about winter-kill of canes or buds as you do with summer bearing types that don't bear until their second year. Fall bearing types are easy for pruning too because canes are cut to the ground every year in December/January and regrow to produce a crop the next season.

Photo credit: Both photos credit Carl Wilson

Prospects for Fruit this Year in Denver

The 2015-2016 winter in Denver was unusually mild for fruit tree flower bud survival with only two days of zero degrees F (December 17 and 28) and no temperatures below zero (National Weather Service DIA records).

February 2016 brought enough warm days that fruit trees with a low chill requirement and low growing degree hours to reach bloom such as apricots and peaches were in flower by mid March.

Apricot in bud March 5

Apricot in flower Mar 19
with snow on branch

March brought fifteen days with minimum temperatures 28 degrees F or below. Overnight lows were 20 degrees F on March 19th and 10 degrees F on March 24. As a rough guide, 28 degrees F is the low temperature where many flower buds showing color or in bloom can be damaged. Prospects for apricot and peach fruit this year are likely poor.

Apple blossoms April 24

April has brought warmer nights. Since April 1st when the overnight low was 25 degrees F, the minimum temperature has not dropped to 28 degrees F.

This means that late blooming fruit such as apple and pear, and even fruit that bloomed slightly earlier such as sour cherry and plum may have fruit this year. Note that the specific location of fruit trees, localized overnight minimum temperatures, health of trees and amount of bee pollination activity are some of the factors that will affect your prospects to develop blossoms, set and grow fruit.

Photo credit: All photos credit Carl Wilson

Turning Under the Winter Ryegrass Cover Crop

As I was strolling the grounds of Denver Botanic Gardens this week enjoying the spring bulb bloom, I saw gardeners turning under a plot of winter ryegrass. This reminded me that cover crops aren't only used in vegetable growing. They can be used anywhere soil improvement is needed including for annual ornamental plantings at DBG.

Growing cover crops has enjoyed a recent rise in popularity in farming as concerns about soil loss have increased. The resulting increase in organic matter from growing cover crops helps in many ways. These include an improvement in soil structure and resistance to erosion, better water penetration and holding, increased soil biological activity, better plant nutrient holding and more. Home and market vegetable gardeners should seriously consider the benefits of cover crops in their efforts.

When growing winter rye for the first time one important question is when to turn it under. Consider this question from two standpoints: 1)how to get the most benefit and least drawbacks in the burial operation, and 2) when you want to plant your vegetable crop.

"Growback" (resprouting)
after turning under

Winter or cereal rye is best turned under when it is between 12 and 18 inches tall and relatively succulent. If turned under when short and still in a vegetative growth stage, there is a pronounced tendency to "grow back" meaning more work in burying plants a second time.

If left to grow until taller than 18 inches, rye enters the reproduction (flowering) stage and tends to have a high carbon to nitrogen ratio due to the high cellulose and lignin content that develops to stiffen stems. This means the plant parts you bury in the soil can be slow to decompose. Note that not only plant height but more so day length promotes flowering. Winter rye flowers when days reach 14 hours in spring.

Chop leaves into small chunks that are easy for soil microbes to attack and digest. In my small home garden plots I use a hedge shears cutting off 2 to 3 inch lengths from the top of the plant and working my way down to the soil line. You can also use a string trimmer to chop plants before incorporation into the soil. Chopping tends to minimize "grow back" because the food supply is cut off from the roots.

The second consideration in when to turn under a cover crop is when you want to plant. Allow a minimum of a month for the leaves and roots to break down before seeding or transplanting. This allows soil nitrogen availability to stabilize after being temporarily tied up by the soil microbes

chewing through the freshly buried rye plants. Once broken down, soil microbes release the nitrogen they tied up making it again available to plants.

Now is generally the time to turn under your winter cover crop if you are planning to plant warm season vegetables in late May or early June.

Photo credit: All photos credit Carl Wilson.

Cover crops for a green winter vegetable garden

Winter rye/Austrian winter pea

Fall planted cover crops make me feel good for two reasons. First I know that after they grow over the winter and I turn them under in the spring, I will have improved my vegetable garden soil. Second is the novelty of looking out my window in the depths of winter and seeing green plants in my vegetable garden.

Plant cover crops in fall from mid-September to mid-October on the Front Range of Colorado. With this year's warm fall weather you probably could have planted through the end of October. The season before we had subzero weather the second week in November so late plantings likely would not have survived. Plants require at least a month of moderate fall temperatures to establish before winter cold slows growth and soil temperatures drop below 40 degrees F.

Winter rye/Austrian winter pea or winter rye/hairy vetch mixtures work well for the Front Range. Many gardeners plant winter (cereal) rye. Grass (the winter rye) alone works well for increasing soil organic matter but if you want the advantage of the nitrogen adding abilities of legumes, add winter pea or hairy vetch in a mixture. Hairy vetch is hardier than winter pea and winter rye is very hardy. Plant at 4 to 6 ounces per 100 square feet except a lower rate of 2 to 3 ounces for vetch.

Water at planting and perhaps once or twice more to establish. In general winter snows will provide enough moisture for plants although you could always winter water in extended warm, dry winter weather if you feel you need to.

In spring spade or till the crop under the soil burying both tops and roots. Keep in mind that after turning under your cover crop you should wait a month for plants to break down before planting vegetable seed or transplants. If you need the garden space to start spring crops and don't have a month to wait, harvest cover crop plants and coarsely chop to decompose in the compost before adding them back to the garden soil between your spring and summer crops.

Cover crops should be a routine part of maintaining a healthy and productive garden soil. Online sources for cover crop seed include Johnny's Selected Seeds and Urban Farmer Seeds.

Photo credit: All photos credit Carl Wilson.