Category Archives: culinary plants

Container Vegetable Gardening

f2t-09378

Colorado State University

Want to grow vegetables but have limited outdoor space or no “dirt” of your own?  Like the ease of growing in pots versus in the ground? Sounds like container gardening is made for you. Here are some helpful tips for successful gardening in pots.

What to Plant

Peppers, squash, greens, potatoes, basil are among the many plants that grow well in containers – check this Planttalk Colorado publication for details and inspiration. When purchasing plants or seeds, look for cultivars described as compact, dwarf, patio or bush. Determinate tomato varieties work well but I also have great success with ‘Sun Gold’, a sweet, prolific indeterminate cherry tomato. (Determinate varieties tend to ripen all at once while and grow on bushier plants, while indeterminate ripen over a longer period and tend to be larger plants.)

Where and When to Plant

Generally, vegetables and herbs need 6-8 hours of sun a day. Placing your container on a strong dolly with wheels allows you to move the plant to find the ideal space. A dolly also helps you quickly shelter your plants from Colorado’s wicked summer hailstorms.

Warm season vegetables such as tomatoes should be planted when evening low temperatures are consistently above 55 degrees. Don’t rush things – in Denver, this generally means late May, even though Mother’s Day weekend is touted as the kickoff to the gardening season.

What Container to Use

squash

Colorado State University

The larger the plant, the larger the root system.  Salad greens successfully grow in pots that are 6-12” deep and at least 18” wide, while a tomato needs at least a depth and width of 14-16″ or more. Larger pots are less prone to drying out rapidly and because they hold more growing medium, the plant receives more nutrients and has plenty of room for root development. Generously sized, heavy containers anchor large plants in the wind and will help avoid tipping and broken branches.

Plastic, glazed or unglazed clay pots or wood whiskey barrels are popular choices. Unglazed clay pots can require more frequent watering, especially in the hottest part of the season. No matter what your container is made of, it must have good drainage holes.

Don’t forget to add support for vining or large plants – stake, cage or trellis your plant just as you would if it was in the ground. These plant aides are easiest to add before the plant needs it. Wrestling a metal cage over a sprawling plant is not fun and may not be successful. I’ve tried.

Soil and Fertilizer

Use potting media specifically for containers and/or vegetables, often labeled soilless.  “Soilless” potting soil sounds like an oxymoron, doesn’t it?  Just like traditional potting soils, it can contain peat moss for nutrients, vermiculite for water retention and perlite to aide in air movement around the roots. The mixture will weigh less and is good to use in heavy containers.

Container veggies grow vigorously and therefore require lots of nutrients. Some mixtures contain time release fertilizers, which help plants get off to a good start, but will not feed plants for the entire season. Excellent information on using soluble and time-release supplements  in our region can be found here.

Penn State Extension noted that time release fertilizers release nutrients faster in warm weather; a pellet fertilizer labeled to last 4-5 months will only last 2 months if the temperatures are above 85 degrees.

According to Colorado State University, “Organic fertilizers such as fish emulsion or blood meal can also be used if desired but may be available too slowly for actively growing plants or may develop sour aromas that attract pets and pests.”

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Parker County Texas Master Gardeners

I’ve always added gravel or broken clay shards to the bottom of  pots for drainage.  Turns out, it’s not necessary or even advisable. Studies by Washington State University and others found that a layer of inorganic material drives excess moisture up to the roots rather than helping with drainage.  Excess moisture suffocates roots and reduces oxygen flow.  So, this year, I’m simply covering the drainage holes with pieces of metal screen to keep soil from leeching out. Paper coffee filters can do the trick too.

When to Water

There is no one-size-fits-all answer to this often-asked question. A best practice is to check plants daily, ideally in the morning. Poke your finger into the soil, if it is starting to dry out at your first knuckle, water at the soil line till water flows out the bottom of the pot. Consider factors such as temperature, wind, reflective heat from surrounding hard surfaces, and as mentioned earlier, the type of container used. In the heat of the summer, you will likely water every day, possibly twice.

Do not allow vegetables to dry out completely – they may not forgive you!  Results of underwatering can include deformed  fruit, poor growth, disease or even loss of the plant.

Conclusion

So there you have it, a round up of solid research-based advice for container gardening. Growing edible plants in pots is rewarding and can yield excellent results. It’s a reliable method for experienced and beginning gardeners alike.  If you’ve never given it a try, its a fun summer activity which can provide plenty of healthy, tasty rewards.

 

Written by Linda McDonnell, Denver County Master Gardener

Growing Hops in the Home Garden

Growing hops at home for brewing or ornamental purposes can be quite rewarding.  However, consistently producing healthy hop plants with good cone yields is a bit of an art, but with experience, it is a process that can be mastered by following a few easy steps.

Hops (Humulus lupulus) is a perennial in the hemp family (Cannabaceae) that produces annual bines from overwintering rootstock.  Hops are native to Europe, western Asia, and North America and are one of the key bittering and flavoring ingredients of beer.

Hops are described as “bines” rather than “vines” because they climb by wrapping around a supporting structure in a clockwise direction and cling to the surface using stiff downward-facing hairs.

Hop plants are dioecious; they have separate male and female plants. Only the female plant produces the cones and lupulin utilized in brewing.  Lupulin is a yellow, resinous substance produced by specialized glands within the cones. Lupulin contains the oils and resins that give hops their distinct aroma. Hops are rhizomes that have underground stems that can produce additional roots and shoots.

Step 1. Selection and Propagation

Cascade, Chinook, Nugget and CTZ varieties will grow well on the Colorado Front Range.  Nugget and Chinook varieties are prolific growers and are very resistant to both insect pressure and diseases.  Rhizomes can be purchased from some homebrew stores, through mail order from many growers, or by propagating established plants.

In Colorado, rhizomes should be divided in late February to early March while plants are dormant. If possible, untrained bines should be coiled around the base of the plant during the growing season and covered with soil. The covered bines will convert to rhizomes, which can be removed in the winter by digging adjacent to the plant and cutting the rhizomes from the plant using a sharp, sterile knife. Ideally, cut the rhizomes into approximately 3-inch lengths with multiple buds.

Stem cuttings can be taken throughout the growing season but are more likely to root when obtained in the spring through early summer before flowering. Several cuttings can be taken from one bine. Dissect the bine so that each cutting has one node at the top, dip the stem bottom in a root toner, and place the cuttings in sand or florist’s fam. Keep the rooting media wet, and roots should develop within 2 weeks. Once roots are well formed, transplant the cutting into a pot with soil and fertilize with a basic fertilizer such as 16-16-16.

Step 2. Establishment and Care

Hop bines normally grow from 15 to 20 feet high but may grow higher depending on the climate and available climbing support. They require full sun (12 hours), good air circulation and well-drained soil with a pH between 6 and 7.5 for high productivity.  A large container such as a half whiskey barrel can also be used and allows you to manage your soil conditions and help keep any unwanted spreading of the rhizomes into your yard.

Once the threat of a killing frost has passed in the spring, transplant the hops into the desired outdoor site. Dig a narrow trench 12 inches deep and slightly longer than the rhizome. Plant one rhizome per hill with the buds pointed up and over with 1 inch of loose soil. They should be spaced three feet apart. Initially, provide consistent watering while being careful to not over water because hops do not like to have “wet feet”.

After establishment, provide climbing support such as a pole or trellis at the planting site. Ideally, string a top wire about 15 to 18 feet high, then attach strings the hops will climb. As an alternative, erect a single pole, which is what most commercial yards did until well into the nineteenth century, and run strings to the top.  The string needs to support plants that will weigh 20 lbs when mature.  If planting two or more hop plants side by side, allow 24 to 36 inches of spacing between plants. If growing for ornamental reasons, a standard trellis or arbor can also work and keep bines pruned to keep desired form. The cones will grow on sidearms as the plant grows.

The focus in the first year of planting is root establishment and not cone production, thus it may be beneficial to limit the plant’s ability to climb during establishment by supplying only a 4-foot stake or pole. Be careful not to remove foliage during the first year because the plants require as much leaf material as possible to develop and store carbohydrates in the root system for the following year’s growth. Plants usually reach full production in their second or third growing season.

Step 3. Train the Bines

As the shoots grow to approximately 3 feet in length, choose the 2-3 most vigorous to grow and remove all remaining shoots. As the shoots elongate, train them onto the support structure by winding them in a clockwise direction, which follows their natural growth habit. Plants may be fertilized during spring and early summer, but fertilizer is not typically required after mid-July. Nitrogen is usually the limiting nutrient for adequate hop growth. You can apply nitrogen as urea (46-0-0) or in combination with other nutrients such as a 16-16-16 fertilizer.

Step 4. Irrigation

Hop plants require consistent moisture throughout the growing season. The plant roots want to be wet but not waterlogged. You may let the soil dry out slightly between waterings. Hop plants grow very rapidly during the heat of summer, so it is important to deliver consistent, even moisture to prevent drought stress. A hop plant may require several gallons of water per day during the summer. Water at the base of the plant to minimize wet foliage which can lead to disease issue.

Step 5. Common Diseases and Insects

Powdery mildew is a common disease affecting hops in our climate.  It is caused by the fungus Podosphaera macularis.  Although unsightly on the foliage, powdery mildew is most problematic when it attacks developing cones during the summer. Cone tissue infected with powdery mildew becomes necrotic and deformed, and chemical composition may be negatively affected. Control measures include spring pruning to remove infected tissue and fungicide application with products such as sulfur.  Many varieties of hops, such as Nugget or Chinook are resistant to the disease.

Spider mites are a common insect problem. A minor infestation causes bronze leaves, while a severe one results in defoliation and white webs. Spider mites are most dangerous during warm dry weather and not usually a problem for well-watered plants.

Step 6. Harvesting and Storage

Hops typically mature between mid-August and mid-September. Hop cones harvested for beer brewing can be used fresh after picking, or dried and sealed in an airtight container in the freezer for later use. Mature cones will have a dry, papery feel, and the lupulin inside of the cone will be golden yellow and have a pleasant “hoppy” aroma. Immature cones will feel soft and vegetative, and the lupulin will be pale yellow with a mild vegetative aroma.

After harvest, cut the bines off the trellis leaving 2 feet of bine above ground.  Do not cut down the last green matter until after the first frost, then prune bines to a few inches and cover with mulch.

Sources:

Hieronymus, S. (2012). For the love of hops: the practical guide to aroma, bitterness and the culture of hops. Boulder (Colorado): Brewers Publications.

Growing Hops in the Home Garden: https://catalog.extension.oregonstate.edu/em9115

Powdery Mildew Fact Sheet: https://extension.colostate.edu/topic-areas/yard-garden/powdery-mildews-2-902/

Aphids on Shade Trees and Ornamentals: https://extension.colostate.edu/topic-areas/insects/aphids-on-shade-trees-and-ornamentals-5-511/

Spider Mites: https://extension.colostate.edu/topic-areas/insects/spider-mites-5-507/

Organic Hops Variety Trials and Over-wintering Study: https://specialtycrops.agsci.colostate.edu/organic-hops-variety-trials-and-over-wintering-study/

 

Written by Kevin Ritter, a Denver County Master Gardener as well as Crooked Stave Artisan Beer Project’s Laboratory Technician and Sensory Specialist.

Photos courtesy of Pixabay.com, a source for royalty free images

Meet the Garden Squad—Gardening Help at the Denver Botanic Gardens

Meet the Garden Squad is a way to get better acquainted with some of our CSU Extension Master Gardener volunteers.

Meet the Gardening Help Volunteers

The CSU Extension Master Gardeners usually pick up the gardening helpline at the Denver Botanic Gardens or answer questions when people walk-in the door. Even though buildings at DBG are closed for now, gardeners can still get their gardening questions answered by Gardening Help from Colorado Master Gardeners at Denver Botanic Gardens, only remotely.

The interest in gardening has soared ever since people have had to hunker down at home and find ways to keep busy. First-time gardeners will likely have questions on how to get started, what to plant now, what can grow in containers, and much more.

Even gardeners with some experience have questions, too. All gardening questions can be emailed to gardeninghelp@botanicgardens.org and a CMG, working remotely, will reply by email.

Gardening Help volunteers include: Back row, left to right: Jan Fahs, Jan Davis, Ken Zwenger, Mark Zammuto, Gordon Carruth, Fran Hogan
Middle row: Lynne Conroy, Harriet Palmer Willis, Kathleen Schroeder, Leona Berger, Cindy Hanna, Mary Adams, Nancy Downs
Kneeling: Dee Becker, Charlotte Aycrigg, Jan Moran
Not pictured: Mary Carnegie, Linda Hanna, Maggie Haskett, April Montgomery, Ann Moore, Kathy Roth, Amy White

Gardening Help is a project of the CSU Extension-Denver Master Gardeners at the DBG. Volunteers provide reliable and research-based information to thousands of home gardeners each year.

Volunteers commit to at least one year in the role, with a minimum of six shifts spread across the year. The commitment starts early in the year with an orientation and training from Nancy Downs, project coordinator.

Many volunteers are GH regulars and they return to the project every year. In addition to being an active CMG, they have to satisfy DBG volunteer requirements, too. That means they’re a member of the DBG and enrolled there as a volunteer.

Some of the key characteristics of GH volunteers are good research, plant identification and diagnostic skills. Because the project is located at DBG, volunteers need to keep on top of what’s blooming at the DBG by season, so they can answer common questions that might pop up.

Photo provided by Nancy Downs

Text by Jodi Torpey
Master Gardener volunteer since 2005

Preventing Tomatoes From Cracking and Splitting

After months of anticipating ripe, sweet tomatoes, my first harvest came a week ago. Unfortunately, several of the inaugural ‘Sun Gold’ cherry tomatoes were cracked around the equator, exposing healthy flesh underneath. Why did this happen and how can it be prevented?

Cracks and splits are a fairly common occurrence. They can start at the stem and run down the side of the fruit, or circle the width of the fruit, like mine did. The good news – the fissures are not the result of a disease, virus or insect. The cause? At least in part – me! On the bright side, I can easily fix it.

Tomatoes crack due to fluctuations of moisture and/or temperature that occur when the fruit is nearly fully mature. In my case, forgetting to water or underwatering a container grown plant on the first few 100 degree days, followed by “forgive me” overwatering for the next few days is the culprit. (Another tip – tomato plants don’t like to get heat wilt. Mine did that too.)

Here’s what happens to cause the fruit to split – during the dry spells, the exterior skin (epidermis) of the fruit toughens. When the plant is watered again, the fruit rapidly takes in the moisture and the fruit plumps up. This expansion causes the toughened skin to burst. Cherry tomatoes and large beefsteak varieties are particularly prone to these stretch or growth marks.

These tips will help prevent tomatoes from cracking and splitting:

  • Tomatoes like consistent moisture at regular intervals. Think of Goldilocks – not too much, not too little. Sounds simplistic, but the point is there’s a delicate balance. Watering on a regular schedule really helps.
  • Use natural mulch such as grass clippings or shredded leaves to keep the plant roots cooler.
  • Fertilize with low dose, slow-release fertilizer; high nitrogen fertilizers stimulate growth which can increase cracking.
  • Pick fruit just before it is fully mature and allow it to ripen on a sunny windowsill.

Some tomato varieties are bred to have more flexible skin and therefore are less likely to crack. When researching next year’s garden tomatoes, look for varieties labeled crack or split-resistant. You may want to give them a try.

Perhaps most importantly – is it OK to eat a cracked tomato? It really depends. Don’t take a chance if the split is deep, the fruit has been on the vine for a long time or you simply aren’t sure. Bacteria can develop in the opening with time. But if the crack has just appeared and the fruit looks healthy despite the scar, it is likely fine. Did I eat mine? I did. And it was worth the wait!

Additional reading: https://hortnews.extension.iastate.edu/faq/why-are-my-tomatoes-cracking

Photo Credit: Pixabay.com

Posted by Linda McDonnell, Denver County Master Gardener

New Mexico Chiles

serrano-peppers pixabay.com

Serrano peppers Pixabay.com

Twenty one varieties of New Mexico chile peppers, Capsicum annuum, will be  on sale on May 18-19 at the CSU Master Gardener Plant Sale held at Denver’s Harvard Gulch Park.  Grown from the University of New Mexico’s Chile Pepper Institute’s (CPI) seeds, the fruits range from mild and flavorful to bold, smoky and hot.

poblano

Poblano peppers New Mexico State University Chili Pepper Institute

The plants will mature in late summer and grow well in Colorado conditions. Mild selections include ‘Conquisstador’ (nonpungent, smooth fruit, strong vines) and ‘Trick or Treat’ (no heat with habanero flavor). ‘NuMex Heritage 6-4’ (award winning fruit, great for green chili), ‘NuMex Joe. E. Parker’ (high yield, excellent for red and green chili) and ‘NuMex Sandia Select’ (high heat level) are among the hot cultivars we’ll have on hand. Find the complete plant list here.

Read on to learn more about New Mexico chile origins, research and growing techniques.

Chiles are native to South America, where they are perennial shrubs. In the United States, with few exceptions such as southern California and parts of Florida and Texas, the plants are grown as annuals. It has been said that New Mexico is to chile peppers what Napa Valley is to wine grapes. The area’s arid climate, hot summers and soil make chile growing conditions ideal. Given Colorado’s similar conditions, the plants grow well here, too.

Scoville_Wilbur_Prof_med

Wilbur Scoville, 1865-1942 New Mexico State University Chile Pepper Institute

Heat and flavor of chile varieties vary greatly and have been studied extensively.  In 1912, mild-mannered appearing Wilbur Scoville developed a system for measuring the feisty flavor of chiles that is still in use today.

According to the CPI, “The heat level of a chile pepper is expressed in Scoville Heat Units (SHU). Scoville Heat Units are intended for comparison only because heat levels can fluctuate greatly from location, and even from pod to pod on the same plant. Chile peppers range in heat from 0 SHU (Bell Pepper) to more than 2,000,000 SHU (Trindad Moruga Scorpion).”

Chile peppers contain chemical compounds called capsaicinoids.  When ingested, capsaicinoids send a message to our brains that the pepper is hot. In large doses capsaicin can burn and irritate humans and mammals. As birds do not have the brain receptors to register this heat sensation, they feel none of the adverse effects of the compound. Because of this, birds are responsible for spreading wild pepper seeds.

The seeds are often, but erroneously, touted as the hottest part of the pepper. In reality, the white flesh near the seeds contain the most capsaicin. When cooking with peppers, leave or remove the ribs depending on your sensitivity.

Beyond heat, chiles offer a wide range of complex flavors. Dr Paul Bosland of the CPI identified five heat profile components. Chile lovers have surely experienced these sensations:

  • Development: Is the heat sensation felt immediately or 5, 15 or 30 seconds later?
  • Duration: How long does the heat linger?
  • Location: Where is the heat sensation felt? Lips, front of mouth, tip of tongue, throat?
  • Feeling: Is it a pin-prick sensation or an overall sensation or does it coat the area?
  • Intensity: Measured by Scoville Heat Units and commonly called mild, medium or hot fruit.

If you’re eager to plant your chiles right now, a word of caution. Plants should be hardened off after the danger of frost by exposing them to outdoor temperatures for longer periods of time daily. Plant in the ground when daytime temperatures hover around 70 degrees and over night temperatures are reliably above 55 degrees.

Before planting, incorporate compost to fortify the soil. Throughout the season, use a balanced fertilizer (5-10-5 or 10-10-10).  Watch for the inevitable dry spells  as plants need at least 2 inches of moisture a week, especially after fruit sets. Night time temperature is critical for flowers to set and is ideally between 65-80 degrees.

What’s your favorite chile pepper? Please share in the comments!

For more information:

Plant Talk Colorado: Chile Peppers

Growing Colorado Peppers, Colorado Farm to Table/Colorado State University

“What’s So Hot About Chili Peppers” Smithsonian Magazine, April 2009

Posted by Linda McDonnell, a Denver County Master Gardener

 

 

Colorado Blueberries: A Success Story

Blueberries grown in peat moss bales

Make no mistake about it, blueberry plants want what Colorado’s soils can’t deliver – high acidity. Attempts to grow them in our alkaline soil will frustrate the most accomplished gardener. However, research at Colorado State University found the plants can be grown successfully in this region when planted directly into a bale of peat moss, which has been tucked into the garden bed. The process is described in detail here.

Five years ago, armed with bales of peat, solid research and determination, Denver Master Gardener Jill Fielder decided to add blueberries to her raised beds. Given the proper environment, regular care and careful plant selection, she’s been enjoying berries every summer since.

According to Jill, “Blueberries are both insect and wind pollinated and the bees love ours. Most experts believe that blueberries set great yields when there’s cross pollination with another variety that flowers at the same time, so we have a couple different cultivars.” Northcountry Blue (small, flavorful berries, upright habit), Bluegold, (productive with a somewhat sprawling habit) and Bluecrop (large berries, the newest addition) are 3.5′ to 4.5′ feet tall and doing well. Northblue didn’t produce well and was replaced.

Spring buds

Plants were purchased on-line from reputable growers and were planted in the spring. The plants are feed monthly during the growing season with a water soluble fertilizer for acid-loving plants. A drip irrigation system provides moisture.

Jill’s raised beds are in a protected area of her yard, bordered by a fence and garage so she has not covered or wrapped the plants in the winter. However, winter protection is recommended in less protected areas. Late in the winter, plants are trimmed to remove dead or damaged wood and maintain shape.

If you’re looking for a new gardening challenge and can commit to the specific needs of these plants, why not give them a try?

Posted by Linda McDonnell, a Denver Master Gardener, with thanks to Jill Fielder for supplying inspiration and photos.

 

 

 

How Vanilla Gets to Your Kitchen

Will you be doing holiday baking this season? If so, chances are your recipes will include vanilla, an often overlooked kitchen staple, with a name that can be synonymous with bland or uninteresting.  But how vanilla gets to our pantry shelves is really quite a feat, in fact, it is anything but vanilla.

Pure vanilla extract is derived from the orchid Vanilla planifolia, a rambling, vigorous vine which grows on tree trunks, can reach 75′ and is native to Mexico and Central America. The plant’s fragrant, yellow to green flowers bloom for exactly one day and must be pollinated while in full bloom in order to produce a vanilla bean. Adding to the pollination complexity, in the wild, each flower has less than a 1% chance of being visited by the plant-specific pollinator, the stingless bee of the genus Melapona. Given these odds, commercial vanilla producers employ a hand pollination technique. Manual pollination was first attempted in the 1840’s by a clever twelve year old boy who worked in vanilla fields on the island of Réunion, east of Madagascar. Hundreds of years later, essentially the same labor-intensive process is still used at commercial plantations.

The flowers are self fertile – containing both male and female parts. The pollination process involves moving pollen from the flower’s anther to the stigma with a toothpick or finger. If successful, in 5-9 months the flower will produce a green bean-like fruit which will be picked and fermented before becoming the dark brown, prized vanilla pod. Once the pods are dried, they are steeped in an alcohol and water mixture to create the extract we bake with and enjoy as an aromatic in perfumes and household products. This video shows the pollination process – not a job for unsteady hands! https://www.youtube.com/watch?v=YOAi2WeLsCs

A few more vanilla facts:

  • The hand pollination process accounts for 40% of the production cost of vanilla, which is why vanilla is so pricey.
  • The FDA has strict standards for vanilla production.  A gallon of extract must contain more than 13 ounces of ground vanilla beans and have at least 35% alcohol.
  • Since the vanilla plant is not a legume, the” beans”  are not beans at all. They are actually pods. 
  • Spiders don’t like vanilla, so the pods can be used to keep these pests away.
  • Vanillin is an essential compound in vanilla. Surprisingly, it is also found in potatoes.
  • Artificial vanilla is created in a laboratory with by-products of the paper industry. That sure doesn’t sound tasty!

Wishing you a happy holiday season, filled with joy, laughter and new found respect for that humble bottle of vanilla!

Credits:

Photos: Pixabay.com

University of Wisconsin Master Gardener Program, Vanilla planifolia

UW Lax.edu, Vanillaplanifolia

Written by Linda McDonnell, a Denver County Master Gardener