Thursday, April 30, 2009

Thinning vegetable seedlings

Thinning overcrowded seedlings is essential following germination. Seedling competition will set back your crop and delay harvest. Some people prefer to thin partially as a hedge against possible later seedling losses. Whether you thin partially or completely to final spacing, do thin. The following photo log provides tips and tells you how. Note that these photos picture thinning for a wide bed or Block style layout, not a row. Wide bed planting results in a greater harvest for your efforts.

Thursday, April 23, 2009

New vegetable garden soils

So you've dug up soil for a new vegetable garden and are less than pleased. Heavy clays, low organic matter content and mixed top and subsoil layers are typical of urban Front Range soils around homes. What are your options?

Just like a human baby can’t do everything that an adult can do, a new garden soil can’t be expected to grow what a long-time garden with carefully cared for soil can. And don’t think that tossing a handful of fertilizer on these tough-to-garden soils will solve your problems. Poor physical soil conditions are the issue, not fertility.

Foot-long ‘Imperator’ carrots are likely not in your immediate future. Perhaps golf ball like ‘Thumbelina’ carrots are a more achievable objective. Better yet, rather than thinking about carrots that require loose soils for root development, consider fibrous rooted, pioneering crops such as lettuce, spinach and kale.

Another thought is to work on soil building your first year. Apply 2 inches of organic compost in the spring and mix in to the top 4 to 6 inches of soil. Plant a summer cover crop such as buckwheat (photo right), till it under in the fall and immediately plant a winter cover crop such as winter (annual) ryegrass. Let the roots of these crops do the work of penetrating these tough soils. Through their burial, add fresh organic matter to feed beneficial soil microbes and build your soil. Ideas on cover crops for Colorado conditions can be found in the CSU Garden Note #244, Cover Crops and Green Manure Crops.

Raised beds with hard sides (wood) or soft sides (soil beds photo left) are another option. Moving or importing desirable soil to construct these beds increases the depth of useable soil and jump-starts your efforts at building a good garden soil. Note that they too will likely require soil building measures such as compost additions and planting cover crops.

A final thought is to avoid overtilling your soil. Beating it up with a tiller is not the answer to building a good soil. Have a good reason to till (turning under a cover crop or mixing in compost for example) and don’t till frequently. Also till at moderate moisture content – not too dry and not too wet. Care for your garden soil and it will care for you.

How do you manage your garden soil? Comments welcome.

Saturday, April 18, 2009

Pear Picks

Pears are a good fruit choice for the Front Range. They bloom late, usually just before apples. Pears are subject to fireblight disease like apples so look for fireblight resistance. Fruit is borne on two year old or older spurs (short, stout twigs) also like spur-type apples.

In choosing a tree for planting, remember that pears are self-fruitful but bear better when planted with a second pollinator tree. Magness is a variety often used for pollination and it shows good fireblight resistance. Any variety that blooms at the same time will serve as a cross-pollinizer.

Both European pears, Asian pears and their hybrids can be grown. Note that Asiatic pears have a lower chilling requirement than European types. Asian pears generally are also less resistant to fireblight.

European pear suggestions include Bartlett (an early summer pear, left in photo) , d’Anjou (right in photo), Bosc and Lucious. Hybrid pears grown here include Maxine (good fireblight resistance) and Kieffer. Of the Asian types, Shinko shows more fireblight resistance.

As in previous fruit tree adaptation discussions [see “Fruit trees on the Front range” March 12], be forewarned that our erratic climate makes this a difficult fruit growing location and these are only suggestions, not recommendations. Comments on your pear growing successes and failures are welcome.

[Pears in basket photo credit, Carl Wilson]

Friday, April 10, 2009

A Tale of Peaches and Potatoes

by guest writer Robert Cox, Colorado State University Extension Horticulturist, Arapahoe County

Gardeners may wonder why they cannot order certain peach trees from out-of-state nurseries. The catalog description may say that the peach variety “cannot be shipped to Colorado”.

There are two quarantines on peach tree shipments in the state. One prevents the shipment of white-fleshed or clingstone peach and nectarine trees into Mesa County, Colorado. This is meant to exclude peach mosaic virus disease from Palisade area orchards.

The other quarantine prevents the shipment of peach and related Prunus (cherry and plum) trees into the San Luis Valley. Peaches can be the winter hosts for green peach aphid that carries potato viruses. When peach aphids move to potato plants in the summer, the crop can become severely diseased and decimate yields.

Some out-of-state mail-order nurseries do not attempt to determine county of residence when a Front Range Colorado customer submits an order for a quarantined peach tree. The nursery may instead choose not to send a quarantined tree to any address in Colorado. While frustrating, little can be done but look for another supplier willing to recognize that your address is not in the quarantine area.

If it’s a small consolation, many states have similar quarantines on plants that could introduce diseases or insects to an economically important crop. Both peaches and potatoes are Colorado agricultural success stories and worth millions of dollars in income to the state.
[Peach photo credit, Carl Wilson]