Extending the Season for Leafy Greens

Are you interested in growing lettuce and other leafy greens?  Are you looking for tips on extending the growing season for your leafy green crop?  If so, then check out this very informative instructional video by Washington County Horticulture Agent Matthew Orwat.

How Did I Get Rust On My Blueberries?

Normally we think of rust as something that deteriorates metal, but a number of different fungal rusts can affect plants in the garden.  Rust disease can affect corn plants, cedar trees, and even blueberry bushes.  Just like the broad range of plant species that can be plagued by rust, there are a number of species of rust fungal spores floating around and ready to infest your garden.  This article will focus on leaf rust of blueberry.

Blueberry rust on top of a leaf.

Blueberry leaf rust on the top of a leaf. Photo Credit: Philip Harmon, University of Florida/IFAS Extension.

Leaf rust of blueberry in Florida is caused by the fungus Pucciniastrum vaccinii.  Although the common name of the disease is “leaf rust”, the disease can also infect the stems and fruit of blueberry plants.  The disease causes small, round spots visible on the tops of leaves.  Spots will multiply and the leaves will eventually yellow and fall off.  Young stems and green fruit can also become infected as the disease progresses.  Bright orange lesions will form on stems and fruit as the thousands of microscopic spores conjoin.  The clusters of spores are easily wiped or washed off of plant material.  When spores dry out, they become airborne and can be transferred to nearby plants.

Blueberry leaf rust on fruit.

Blueberry leaf rust on fruit. Photo Credit: Philip Harmon, University of Florida/IFAS Extension

The rust fungus thrives in hot, humid, wet conditions.  A number of cultural practices can be adopted to reduce disease progression and survival.

  • Irrigation

    Disease persistence can be reduced by limiting the amount of water that contacts the plant leaves.  Water the base of plants or install drip irrigation for your bushes rather than watering from overhead.  If overhead irrigation is the only option, then water plants in the morning rather than in the evening.  This allows the leaves to dry out over the course of the day.

  • Pruning

    Removal of approximately 25% of the oldest canes in late winter before spring growth begins will stimulate the production of new canes and should result in plants with canes of different ages and will provide a good mix of vigorous branching and fruit production.  Moderate summer pruning can also improve yield and shoot growth. When pruning, cut out vigorous shoots that are growing well beyond the desired canopy height and are in the interior portion of the bush.  This will promote a more open growth habit and help with air circulation on the remaining plant material.  Some vigorous canes developing from the ground and growing on the outside of the bush can be topped to stimulate branching and flower bud formation.

  • Mulch

    Pine bark mulch helps with establishment of young plants and helps keep soil pH low in existing plantings.  A layer of aged pine bark 3 inches deep extending about 2 feet out from the plants will provide a good growing medium for surface feeder roots.  Pine straw can be used if pine bark is unavailable.  Mulch also moderates soil temperature, helps keep weeds at bay, and adds organic matter to the soil.  Make sure to keep mulch raked back about three inches away from the plant canes to provide good air circulation to the roots.

Hopefully this article has given you some tips to have a good blueberry crop for years to come.  For more information on growing blueberries in Florida, please visit the University of Florida/IFAS EDIS Publication: Blueberry Gardener’s Guide.

Be Proactive to Ward Off Armillaria Root Rot

Be Proactive to Ward Off Armillaria Root Rot

Recently, an Extension Agent in the Florida Panhandle received a picture of some mushrooms popping up in a client’s garden.  These particular mushrooms were in a spot where leftover mushroom compost had been dumped.  The compost was previously used to grow oyster mushrooms and the client was hopeful that she had more oyster mushrooms growing in her yard.  Unfortunately, the lab results came back stating the mushrooms in question were Armillaria spp.

Armillaria spp.

Armillaria spp. in the garden. Photo Credit: University of Florida/IFAS Extension.

Armillaria spp. cause root rot of trees and shrubs throughout the world.  The fungus infects the roots and bases of trees, causing them to rot and eventually die.  Some species of Armillaria are primary pathogens that attack and kill plants, but most are opportunistic pathogens that are attracted to unhealthy or stressed plants.  Fruiting structures of the fungi can be recognized by the clusters of yellow to brown-colored mushrooms that emerge during wet conditions.  However, the mushroom caps sometimes never form and the plant material needs to be inspected more thoroughly to find the disease culprit.  Infected plants may have wilted branches, branch dieback, and stunted growth and should be removed and replaced with resistant species.

White mycelial fan under the bark of a root.

White mycelial fan under the bark of a root infected with Armillaria tabescens. Photo Credit: Ed Barnard

Management – The best method for controlling Armillaria root rot is with proper plant installation and maintenance.  Planting plant material at the proper depth will allow the roots to breathe and reduce the opportunity for the roots to rot.  Pruning tools should be sanitized between plant material.  Proper irrigation and fertilization will also reduce the risk of plant disease and root rot.  Lastly, you can choose to plant a diverse landscape with resistant species.

For more information on Armillaria root rot and a comprehensive list of resistant species, please view the EDIS publication:  Armillaria Root Rot

Sweet Potatoes for the Summer

Sweet Potatoes for the Summer

This late winter has been alternating between warm and cool extremes. One thing is for certain and that’s that it’s time to start planning your sweet potato crop.

Sweet potatoes are generally planted March through June in the Florida Panhandle. The most common method of planting is with sweet potato slips. Sweet potato slips are simply six to eight inch cuttings of a sweet potato vine with the majority of the leaves pulled off. You can purchase sweet potato slips from a local garden center or a seed catalog. Make sure you only purchase certified, disease free slips. You can also easily start your own sweet potato slips from a store-bought sweet potato.

Sweet Potato Slip Production

  1. Pre-sprout Your Tubers – Place sweet potato tubers in a warm place (75 to 85 degrees) with high humidity (90%), such as in your garage, for two to four weeks. It is important that you put the tubers in a well-ventilated container. Allow the tubers to stay in the pre-sprout area until sprouts are roughly 1/4-inch in length.
  2. Bedding – Sweet potatoes are placed in “beds” to produce slips. A sweet potato bed can be made out of the same materials as you’d use for a raised bed garden. You can simply build a frame out of 2″x12″ lumber. Plastic is placed in the bottom of the beds before a layer of bedding material is put down. The bedding media can be a peat-based potting mix or a more economical substrate would be wood chips or sawdust. Sprouted sweet potatoes should then be placed in a single layer 8″ to 12″ inches apart and covered with two additional inches of bedding material. Then top dress the bed with a general purpose, granular fertilizer, water the bed, and cover with clear or black plastic. Poke holes in the cover plastic to aerate the soil and prevent carbon dioxide and temperature buildup. You may need to water the bed periodically, but do not completely saturate. Sweet potato slips can also be produced in the garden if you have a sandy, well-drained soil such as the field pictured below.

    Sweet potato slip production in the field. Photo Credit: Evan Anderson, University of Florida/IFAS Extension.

  3. Cut Slips – Slips will be ready to cut in seven to ten weeks. Cut slips 1″ above the bed surface and trim to 10″ to 12″ in length.  Strip all but the top one or two leaves from each slip. If you are unable to plant your slips at the time of cutting, then store them in a cool, dry area to prevent them from rotting.

Rooted sweet potato slips that are ready to transplant into the garden when the soil becomes warm.
Barbara H. Smith, ©2016 HGIC, Clemson Extension

Sweet Potato Production

Sweet potato slips can be planted March through June in the Florida Panhandle. Plant the slips at least three nodes (leaf stubs) deep at 12″ by 36″ spacing. Fertilize based on soil test recommendations. Sweet potatoes are ready to harvest generally between 100 to 120 days after planting slips. After harvest, you will need store your sweet potatoes in a warm (80 to 85 degrees), humid (80 to 90%) place for one to two weeks to allow them to “cure”. After the curing period, you can store your sweet potatoes in a cool area (55 to 60 degrees) until you are ready to eat them.

Sweet potato storage on a commercial farm. Photo Credit: Evan Anderson, University of Florida/IFAS Extension.

Still Time to Register for the Panhandle Fruit & Vegetable Conference!

Register today for the 2018 Panhandle Fruit & Vegetable Conference!  The Panhandle Fruit & Vegetable Conference is scheduled for February 19th & 20th.  On the 19th we will go on an afternoon farm tour in Baldwin County, AL that will end with dinner (included) at Auburn University’s Gulf Coast Research and Extension Center in Fairhope.  Educational sessions with guest speakers from University of Florida, Auburn University, and Texas A&M University will be held on February 20th where topics will include Citrus Production, Vegetable Production, Protected Ag Production, Marketing/Business, Food Safety, and Fruit & Nut Production.  A full list of topics can be found here.  Fifty dollars (plus $4.84 processing fee) covers the tour and dinner on the 19th and educational sessions, breakfast, and lunch on the 20th!  The complete agenda is now available.  Use your mouse or finger to “click” on the image below for full screen viewing.

Make sure to register by Wednesday, February 14th! – Registration Link