Video: Downy Mildew In Hops Plants

Downy Mildew is caused by the notorious plant pathogen, Pseudoperonospora humuli, an organism that is considered by biologists to be an oomycete protist. Pseudoperonospora results in reduced yield, poor hop quality, and, in severe cases, plant death.  With an ever-increasing number of gardeners, home, and local brewers interested in growing their own hops, it is essential that they understand the cause and symptoms associated with this severe pathogen. If you grow hops, you should read this short article, then watch the video explaining the life cycle of downy mildew in hops plants

Symptoms Of Downy Mildew In Hops Plants

Growers begin to see signs of downy mildew in early spring.  Pseudoperonospora affects hops plants grown in containers and hopyards. It is one of the most important diseases of hops that are grown in wet and humid regions. Mild temperatures (~65°F) and moisture resulting from rain, overhead irrigation, and morning dew are ideal conditions for infection. Microscopic flagellated zoospores are produced which swim on the surfaces of a leaf, entering through plant stomata and setting up an infection.

 

hops plant with downy mildew
The underside of hops leaves showing discoloration due to the formation of oomycete sporangia

Leaves that are infected have black lesions while cones that are infected become brown, harden, and sometimes do not develop correctly. Pseudoperonospora continues to grow and invades the hop tissues, eventually killing healthy plants. The infection moves throughout the entire plant, including the bines, buds, and rhizomes. More zoospores are produced on the underside of leaves, which becomes blackened with masses of sporangia.

Video: Downy Mildew In Hops Plants

Click on the video and see the life cycle of Downy Mildew and how it infects hops plants.

A Change In Classification

For many years, biologists believed that oomycetes were true fungi.  In fact, the “mycete” suffix is reserved for fungi.  The basis for its classification was based on filamentous cells and the formation of sporangia, which are common characteristics of true fungi. With more advanced techniques available to biologists, there is now evidence that oomycetes are not related to fungi and are more closely associated with a group of protists called Stramenophila. So even though their placement on the tree of life has changed, their name has not.

What Makes Oomycetes Unique?

Oomycetes are unique organisms that differ metabolically, genetically, and in their cell structures.  Pseudoperonospora is an obligate plant pathogen, meaning that it requires a living cell to complete its life cycle. Additionally, this organism produces motile zoospores with two flagella.  One flagellum is whiplike, while the other is a ‘tinsel’ flagellum.  This important characteristic is another reason why they are now classified as Stramenophila.

There are several differences between the characteristics of oomycetes and fungi. For example, the cell walls of Pseudoperonospora are composed of cellulose rather than chitin, and their cells typically do not have septations. Another difference is in the vegetative state that is composed of diploid nuclei, whereas fungi have haploid nuclei. Additionally, oomycetes and fungi have different metabolic pathways for synthesizing the amino acid, lysine, along with enzyme and mitochondrial differences.

Choosing Pseudoperonospora Resistant Varieties

Listed below are hops varieties that are moderately resistant and resistant to downy mildew.

Hops Variety Usage Downy Mildew Susceptibility
Columbia Aroma Moderately Resistant
Fuggle Aroma Moderately Resistant
Hall. Gold Aroma Resistant
Hall. Magnum Bittering Resistant
Hall. Tradition Aroma Resistant
Newport Bittering Resistant
Perle Aroma Resistant
Spalter Aroma Resistant
Sterling Aroma Moderately Resistant
Teamaker Aroma Moderately Resistant
U.S. Tettnanger Aroma Moderately Resistant
Willamette Aroma Moderately Resistant

Currently, growers manage downy mildew by removing basal foliage during spring pruning and frequent applications of fungicides.  An extensive list for Disease Management and Control for both gardeners and large scale conventional growers can be found at the North Carolina State Extension.

Citation: Judelson H. 2007. Sexual Reproduction in Plant Pathogenic Oomycetes: Biology and Impact on Disease, p 445-458. In Heitman J, Kronstad J, Taylor J, Casselton L (ed), Sex in Fungi. ASM Press, Washington, DC. doi: 10.1128/9781555815837.ch27

 

Growing Parsley in Containers

Parsley is a hardy plant, easy to grow, and has amazingly great flavor. Garden parsley, Petroselinum crispum, is a species of flowering plant in the family Apiaceae and is widely cultivated as an herb and a vegetable. It grows as a biennial, in the first year, it forms a rosette of leaves, with numerous leaflets and a taproot for energy storage. In the second year, it grows a flowering stem with fewer leaves topped with yellow flower umbels. Learn how to grow parsley in containers, it’s fun and easy, not to mention all you will have all that parsley for your recipes.

garden-parslely

Parsley types to grow: Curly Leaf Parsley (Petroselinum crispum neapolitanum)  is used mainly for garnishing and in salads. This type of parsley has thicker ruffled leaves, a bright green color, and a muted flavor that gets more bitter over time.

Flat Leaf Parsley (Petroselinum crispum) has a stronger and sweeter flavor than any other type of parsley and it makes an excellent choice for cooking. Italian flat-leaf parsley adds a fresh flavor to any dish. Use it in soups, stews, and salads. This variety grows taller and lanky and requires a wider pot to grow into. Additionally, the flat-leaf parsley is more heat tolerant than other varieties.

Growing parsley from seed: You can purchase established plants from a local nursery, but you’ll get more plants for less money if you start with parsley seeds. Check out our article on starting seeds indoors.  Parsley seeds are notorious for their low and slow germination rate that can take up to 6 weeks to germinate so plant as early as possible. We usually wait until the plants are about five inches tall, and then those plants are transplanted into containers and grown outside or on a sunny window sill. The advantage of growing parsley in containers is that you can move the plant to a new location to optimize its growing requirements.

Choosing a pot and growing requirements: For growing parsley choose a rather large pot, 10 to 12 inches deep and wide. The container must have drainage holes. You can grow as many as 4 plants in this size container. Parsley grows best in moist, well-drained potting soil. You can also add aged compost to the container to supplement nutrients. Parsley in containers should reach 12 to 18 inches in height. It grows best between 72–86 °F and requires full sun. Remember that parsley in containers requires constant watering throughout the season. One container is plenty for an average family.

Harvesting Parsley in Containers: Harvest parsley leaves when needed in your favorite recipes. You can start harvesting parsley about three months after planting. Wait until the stems and leaves have matured. Cut the entire stem carefully from the base as parsley stems are also edible and tasty. Work from the outside of the plant and let the inner portion continue to grow.  Think of parsley as a continual harvest crop but do not over pick your parsley, give it some time to grow back. Pick the dead and faded leaves from time to time to keep your plant in shape and looking good. If flower stalks develop remove them to promote green foliage growth.

 

 

 

 

Growing Hops In A Container

hops cones

What do you do if you want to grow hops, Humulus lupulus, and you have limited space?  Not every craft brewer has access to a plot of land or even a backyard. Maybe you live in a condo with a sunny balcony or maybe there’s just not enough room to build a hops arbor.  So if you are living in the urban jungle, then the answer is to grow hops in containers.  You can do it! It’s easy and with these gardening tips you will get up to speed and growing hops in no time.

Scout the location:

Hops love the sun so pick a location that receives adequate light throughout the day.   This can be a porch, patio, deck, driveway, yard or anywhere that gets the right amount of light. Put some effort into your decision, you need to find an area that gets as much sun as possible from the late morning to afternoon. Hops grow vigorously within USDA hardiness zones 4 through 8. Hops are a hardy perennial plant that will actually thrive in climates that experience all four seasons.

Get your rhizomes:

There are many different varieties of hops to choose from based on key factors for brewing.  We chose to grow Centennial hops, the rhizomes are pictured below.  The first three are healthy with new bud growth and root production. The last shows little development yet it was still viable. Remember, you are planting female plants since they produce the hops cones necessary for  brewing.  Chances are you will order hops online.  We ordered these from a seller on eBay. If you receive rhizomes by mail, refrigerate them prior to planting.

hops rhizomes

Alpha acids from hops contribute to the bitterness in beer. The more alpha acids the more bittering potential. The actual alpha acids vary from year to year depending on the weather, harvest conditions, and storage. Here is a list of common hops and their alpha acid content.

Common Hops Alpha Acid Content
Cascade 6
Centennial 10.5
Chinook 13
Citra 11
Galaxy 13.5
Mosaic 11.5
Willamette 5.5

Planting time:

Obtain a half-barrel planter or another container with a diameter and depth of at least 20 inches. Make sure the container has several holes along the bottom to allow for adequate drainage. Fill the pot with potting soil, dig a 4″ trench and lay the rhizome in with the buds upward and root facing downward then cover with adequate potting soil.  We made a sturdy trellis from garden fencing. Despite their large size, hops grow well in containers and if provided with abundant water and ample supplemental nutrients they will produce, to your delight, an abundance of cones.

Care and Feeding:

Be sure to water your hops as needed, thoroughly wet the soil in the container.  Never let your plants begin to become dry, brown and brittle. These are indicators that your little plants are asking for more water.  Alternatively, if they begin showing discolored, yellow leaves, then dial back, they are probably receiving too much water. Feed container-grown hops plants with a liquid fertilizer diluted to quarter-strength. Apply the fertilizer every four weeks from the time the vines emerge to when they begin to develop cones.

Training Time:

As your hops grow in length, they need to be attached to the trellis.  Weave the bine in and out in a clockwise direction for best results. Prune the hops bines once they overgrow their trellis. Remove the leaves from the lower 1 foot of bine to increase air circulation and decrease the likelihood of pests and disease.

Harvest:

As summer passes and fall begins, it is time to start thinking about harvesting your hops! You should expect to begin harvesting sometime between mid-August and September. As the cones reach maturity, the tips of the cones will begin to turn light brown.  First-year plants may produce as much as ½ pound of hops, while established plants can produce in excess of 2 pounds per year.

 

 

 

How to Grow Raspberries in Containers

Imagine how great it would be to start your day by picking delicious raspberries for your morning smoothie or breakfast cereal. Homeowners with limited space can grow berries in containers and it’s really not a hard thing to do. What’s important is to select the best variety, the right container, and a sunny location. For gardeners with limited space or for apartment dwellers who grow on a porch or patio, growing berries in containers allow a level of flexibility not realized by inground plants.  In this post, we will give tips for successfully growing raspberries in containers.

growing raspberry plants

Choosing the right variety:

Berry plants are great candidates for container gardening, especially if you pay careful attention to which varieties you choose to grow.  Some raspberry varieties are just too large to grow in containers. Fortunately, plant breeders have been busy at work producing container-friendly plants.  Newer cultivars like Raspberry Shortcake® a dwarf, thornless variety, are best suited to growing in large pots.

Choosing The Right Container:

When choosing a pot, always opt for the largest container possible. Plan on needing a minimum volume of eight gallons per raspberry bush. Do not pick a tapered pot and regardless of its size, there should also be a drainage hole in the bottom of the pot. Roots allowed to stay in standing water will eventually rot. Fill the containers in your small-space garden with a 50/50 mixture of potting soil and compost. Mulch the soil surface to reduce water loss.

Sun Requirements:

All fruiting plants, whether you’re growing raspberries in containers or in the ground, produce the most berries in full sun. Provide at least six to eight hours of sun per day. Planting in containers provides for the flexibility of moving plants to different patio locations to receive full sun each day.

Pruning:

Raspberries are perennials that usually set fruit on two-year-old canes. Sometimes plants may produce fruit in the first year, however, full bearing begins in the second year.

Final Tips:

  • Raspberry Shortcakes® grow successfully in large containers
  • Grow in full sun
  • Water regularly
  • Fertilize with an organic fertilizer in early and late spring
  • Let the raspberry bushes go dormant in winter, protect from deep freezing
  • After three years transplant your raspberries from container to inground

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