Rain at last - more needed

The official Denver precipitation total is now up to 0.84 inches for April (still 0.45 below normal for the month though). People closer the foothills received more rain during the upslope weather late in the week. Seedlings are coming up below the poly germination blanket (photo left) even without added sprinkling. See how to use this germination aid in previous post.

The name of the game now is to keep moisture on and through your soil. This is particularly true if you have added compost or turned under a winter cover crop for soil improvement.

Remember that the melding of the organic matter into the soil relies on microorganisms and they aren't active unless there is sufficient moisture. Turned under winter cover crops like rye and Austrian winter pea need a month to break down before planting vegetables IF the soil is moist enough for the microorgaisms to work over the buried plants.

Compost will release nitrogen during the growing season in addition to improving the structure of the soil. Again, soil moisture is needed for this to happen.

Check not only surface moisture, but also subsurface moisture content. After a dry winter, initial rains may have only moistened the top few inches. You may have to add supplemental moisture to wet the soil throughout the soil "profile." How does your soil moisture look down 6 to 10 inches?

Photo credit: Germinated seedlings under blanket - Carl Wilson

Dry spring weather

Both low precipitation and frequent drying winds have dogged Front Range gardeners trying to germinate vegetable seeds this spring.

Many of the cool season vegetable seeds planted at the beginning of the season are small and can't be planted deep. These include broccoli, onions, lettuce, kale and radish. Being near the surface leaves them vulnerable to drying out during the days-to-germination period. If seeds start germination and then dry before emergence, they often perish.

What to do? In addition to frequent, light watering, the use of straw mulch or germination blankets can help. A useful germination blanket is spun polyester floating row cover fabric tacked down with wire U-pins. These fabrics gerenally allow 85% light transmission as well as passage of moisture through to the soil.

Blanket removal immediately upon seedling emergence is not mandatory and can be delayed until several true leaves have formed and seedlings are well established - that is if fabric is anchored loose enough to "float".

Photo credit: Floating row cover seed germination blanket, Carl Wilson

Vegetables 101 class

Learn the keys to successful vegetable growing on the Front Range including tips and tricks to make your gardening life easier. Colorado’s climate realities include a short growing season, cool summer nights, dry air, erratic late spring and early fall frosts. Soil conditions add another gardening challenge.

The guiding hand of you, the grower, makes all the difference in adjusting growing conditions to achieve results. Come learn when and how to intervene to produce the vegetables you want for fresh eating and preserving.

Instructor: Carl Wilson, writer of Front Range Food Gardener

and CSU Extension horticulturist in Denver

For: Beginning to intermediate gardeners

Dates: Saturday, March 19, 2:30 to 4:30 p.m.

repeated Saturday, April 16 2:30 to 4"30 p.m.

Location: 200 Santa Fe Dr., Denver

Click to Register: Denver Urban Homesteading

Cost: $25

Photo credit: Seedlings in spring garden before thinning, Carl Wilson

Get Ready at Garden Symposium

Get growing ideas at the Urban Farmers and Vegetable Gardeners Symposium scheduled for Saturday March 12 on the Auraria campus in Denver. The day includes presentations on specialty vegetable and fruit growing topics presented by the author of this blog, Carl Wilson, other CSU Extension personnel and Feed Denver instructors. You can choose six classes during the day from eighteen classes available as outlined below. For more information and to register, visit the Feed Denver website.

9:00
Connecting with Tasty Small Fruit - Joel Reich
Vegetable Seed Starting Secrets - Patti O'Neal
Sustaining Yourself in Changing Times - Kate Armstrong

10:00
Hear The Buzz - Bees and the Edible Garden - Beth Conrey
Lessons from the Vegetable Garden - Carl Wilson
Coming into Community through Urban Food - Kate Armstrong

11:00
Fruit Trees that Earn their Keep on the Front Range - Carol O'Meara
Tips and Tricks for Tomato Growing - Patti O'Neal
Urban Gleaning, Gathering and Foraging - Kate Armstrong

1:00
The Living is Easy Summertime Vegetables - Carol O'Meara
Troubleshooting Insects in the Vegetable Garden - Mary Small
Farming for Climate Change - Ariel Chesnutt

2:00
Vegetables are Cool in Spring and Fall - Carl Wilson
Healthy Soil makes the Vegetable Garden - Jean Reeder
Planting for Your Family's Food Needs - Sarah Marcogliese

3:00
Vegetable Garden Pests: More than Insects - Mary Small
Growing Vegetables in Small Spaces - Cathy Jo Clawson
Food not Lawns - Ariel Chesnutt

* Presented by: Colorado State University Extension, Feed Denver Urban Farms & Markets, Compost Auraria

Soil testing a good idea

Now that the latest snow has melted, it's a good time to collect and submit soil for testing ahead of spring soil preparation and planting. Do be sure to air dry soil first before shipment.

I've seen both extremes over the years - too little fertility to produce good vegetables and over-fertilization that causes problems. Nationally studies show over-fertilzation is more of a problem in home gardens.

Excess nitrogen applied to tomatoes, squash and other "fruiting" vegetables produces luxuriant leaf growth and few fruit. With root crops such as carrot, turnips and parsnips you will see many leaves and small roots. Little nitrogen when corn tassels produces poor ear production.

Excess phosphorus tends to interfere with vegetables' ability to absorb iron and other micronutrients. The excess shuts down the roots production of phytochelates, organic molecules that increase iron uptake.

You can see that a general broadcast of a 5-10-5 or 10-10-10 fertilizer without knowing where you stand on fertility is likely a poor idea.

Sample prior to adding compost or fertilizer and send to the Soil Testing Lab at Colorado State University or another analytical lab for analysis. The soil test results will inform you about whether compost should be added and what type. For example a salt-affected soil with low organic matter will require low-salt compost (often plant-based and not containing manure).

Testing your soil on a three to four year cycle is usually enough to do a good job of managing the fertility and organic matter in Colorado soils. For more information check the Colorado State University Extension fact sheet Fertilizing the Vegetable Garden.

Photo credit: Collecting soil sample - Carl Wilson

Roots time

With colder weather setting in Thanksgiving week, it’s a good time to explore your underground growing success by digging root vegetables. Beets are a good example, the cool weather causing them to be extra sweet.

‘Chioggia’ beets named for a town across the bay from Venice are pictured here. They are a 65 day, Italian home garden variety with festive red and white striped interior rings. Try them roasted with feta cheese. Sweet!

Carrots are another mainstay. ‘Nelson’ (pictured) is a half-long variety well adapted to growing in our shallow, clay soils. A Nantes type, it grows 5 to 6 inches long in 58 days. It consistently produces smooth, high quality roots with great uniformity.

Make fresh harvested roots a part of your November vegetable menu.

You can store roots in the garden longer into December and even January by covering them with a blanket of mulch. A foot deep layer of fallen tree leaves weighted with wire fencing or staked with netting to hold them in place should do the trick.


Photo credits: Dug 'Chioggia' beet root, 'Chioggia' beet slices, dug 'Nelson' carrot - all Carl Wilson