The Effects of Mixed Hardwood Biochar, Mycorrhizae, and Fertigation on Container Tomato and Pepper Plant Growth

Biochar (BC) has the potential as a peat moss alternative for container plant growth. Three experiments were conducted to evaluate the effects of mixed hardwood BC, compost types, mycorrhizae, and fertigation on container-grown tomato and pepper growth. In experiment 1 (Exp1), BC at 50%, 70%, and 90% (vol.) were mixed with 5% vermicompost (VC) with the rest being a commercial peat moss-based substrate (CS) and fertigated at 200 or 300 mg L−1 N. In experiment 2 (Exp2), 80% BC was mixed with chicken manure compost (CM; 5% or 10%) and CS and fertigated at 100 or 200 mg L−1 N. In experiment 3 (Exp3), 90% BC was blended with CS and fertigated at 200 or 300 mg L−1 N. Mixes in all the three experiments were added with or without mycorrhizae. Results showed that, compared with CS, in Exp1 tomato and pepper plants grown in BC-VC mixes had similar soil-plant analyses development (SPAD), growth index (GI), and total dry weight (TDW); in Exp2 and Exp3, plants in BC mixes (80% or 90%) had lower GI and TDW. In conclusion, BC (≤70%) amended with VC mixes could be used for container tomato and pepper production without negatively affecting plant growth, while BC (80%, 90%) mixes could have some negative impacts on plant growth.

Phytophthora pathogens threaten rare habitats and conservation plantings

Phytophthora pathogens are damaging native wildland vegetation including plants in restoration areas and botanic gardens. The infestations threaten some plants already designated as endangered and degrade high-value habitats. Pathogens are being introduced primarily via container plant nursery stock and, once established, they can spread to adjacent areas where plant species not previously exposed to pathogens may become infected. We review epidemics in California – caused by the sudden oak death pathogen Phytophthoraramorum Werres, De Cock & Man in ‘t Veld and the first USA detections of P. tentaculata Kröber & Marwitz, which occurred in native plant nurseries and restoration areas – as examples to illustrate these threats to conservation plantings.

Stability and Maturity of Different Poultry Manures and Potential Utilization for Horticultural Production

This study evaluated stability, maturity and the efficacy of different poultry litter for possible use in container plant production. Three types of poultry manure- Battery cage (BC), Deep litter (DL) and Free range (FR) were used, with Kraal manure (KM) as a comparison. The experiment was set up as a Split- split design with 6 replications. Composting period was main plot, poultry manure type the split plot and mixing ratio as the split- split plot. The litter was mixed with garden soil in 2 ratios (3:1 and 1:1 soil: manure ratio) and tested for up to 12 weeks. Rape (Brassica napus) was used as a bioassay for maturity, which was determined at 1 month, 2 months and 3 months. The pH declined slightly from 7 to about 6 for all treatments except for the kraal manure. Respiration trends were similar to electrical conductivity. Within 2 weeks of curing the respiration rate for all manures declined to below 4 mg CO2- C/ kg. At the end of 12 weeks curing Battery cage had highest total nitrogen (2.32 %), followed by Free range (1.25 %), Deep litter (0.73 %) and Kraal manure was lowest at 0.35 %). Maturity (rape survival) increased with compositing time. After 3 months of curing Kraal manure had highest survivability of rape. The DL at 1:1 ratio had the lowest survival of 67%. At 12 weeks except for BC at 3:1 all treatments had 100 % survival. The results showed that nitrogen rich manures (DL and BC) needed longer curing in order for them to reach maturity.

Production of Three Eastern U.S. Native Shrubs: Effects of Auxin Concentration on Rooting and Shade Level on Container Plant Growth

American fly honeysuckle (Lonicera canadensis), hobblebush (Viburnum lantanoides), and sweetbells (Eubotrys racemosa) are eastern U.S. native shrubs with ornamental value, which might become successful nursery crops if they propagate readily from stem cuttings and grow uniformly in containers. We evaluated rooting success for hobblebush and sweetbells using stem cuttings treated with indole-3-butyric acid (IBA) in talc at concentrations of 0, 1000, 3000, or 8000 ppm. For hobblebush, IBA at 1000, 3000, or 8000 ppm will yield 70% rooting success. For sweetbells, IBA treatment did not enhance rooting, and 88% rooting success can be achieved with untreated cuttings. Stem cuttings of american fly honeysuckle root at 49% (previously published). We also evaluated all three native shrubs grown in nursery trade #1 containers under shade levels of 0%, 40%, or 70%. American fly honeysuckle grown under 40% or 70% shade were larger, had a greener hue angle, and higher chlorophyll fluorescence (Fv/Fm) than plants grown in full sun. Throughout the study period, Fv/Fm values for full-sun american fly honeysuckle were 0.6 or below, indicating plants were stressed. Hobblebush in 40% and 70% shade were wider, had more leaves, and enhanced foliage color compared with full-sun plants. Hobblebush in 70% had the highest Fv/Fm values at 0.78 or higher across the study period. For sweetbells, plant width increased as shade level increased. Even though sweetbells in 70% shade were wider and larger, they lacked density and had a less appealing habit than 40% shade and full-sun plants. Of the three study species, sweetbells might be the easiest plant for growers to incorporate into production because it propagates readily from stem cuttings and can be grown in full sun to 40% shade. Hobblebush and american fly honeysuckle may present more challenges for growers because hobblebush requires considerable shade to grow and american fly honeysuckle is more difficult to propagate.

Development and Evaluation of Diploid and Polyploid Hibiscus moscheutos

Hibiscus moscheutos L. is an herbaceous hibiscus native to eastern North America that has been a popular landscape and container plant exhibiting large and colorful flowers in the summer. However, unsightly fruit develop and remain on the stalks at the end of the blooming season, which greatly decreases the ornamental value. Thus, breeding for sterility was attempted through ploidy level manipulation to reduce formation and growth of seed stalks, and to improve blooming vigor and longevity. Colchicine and oryzalin were used as mitotic inhibitors to induce tetraploid breeding lines that could be used to develop sterile triploids. Germinated seedlings of ‘Luna Red’ were soaked in three concentrations of each doubling agent for three different durations. Exposure to a low concentration of colchicine solution for a long time or to a low concentration of oryzalin for a short period was found to be effective in yielding a high number of tetraploids with a low rate of mortality. Triploids were obtained from the traditional method of crossing tetraploids with diploids. Triploid and tetraploid plants showed a decrease in height with a more compact form. Leaves of tetraploid plants were more ruffled, with an increase in overall leaf thickness, but were not different from leaves of diploids and triploids in regard to leaf mass per area (LMA). Triploid plants bloomed longer but had smaller flowers than diploid plants. Although the whole planting was infected by aerial phytophthora, diploid, tetraploid, and triploid plants were significantly different in their tolerances: all diploid branches were infected, but only a minor infection occurred on one triploid branch, and the transmission remained slow. Flowers of tetraploid plants failed to produce pollen, whereas flowers of triploid plants produced only nonviable pollen grains and fruits aborted after pollination, which led to infertility of induced triploids.

Effects of Woody Mulches and Dimethenamid-P on Container Grown Ligustrum japonicum and Viburnum macrocephalum

Current weed control practices in nursery container plant production consist primarily of hand weeding and application of preemergence herbicides. Non-chemical weed control methods, such as mulches, could reduce herbicide use, reduce potential environmental concerns from offsite herbicide movement, and decrease the expense of weed control. Before implementation, alternative methods of weed control must be evaluated for effects on the growth of common container-grown species. Mulches made from readily available tree species, including eastern red cedar (Juniperus virginiana), ground whole loblolly pine (Pinus taeda), Chinese privet (Ligustrum sinense), and sweetgum (Liquidambar styraciflua), were evaluated at multiple depths with and without the herbicide dimethenamid-P (Tower®). Wax-leaf ligustrum (Ligustrum japonicum) and snowball viburnum (Viburnum macrocephalum) treated with dimethenamid-P, averaged over mulch treatments, had up to 7% less growth compared to non-herbicide treated plants, but marketability was not affected. Mulch species and depth had no effect on plant growth. Results indicate that these readily available mulch species can be applied at depths up to 10.2 cm (4 in) for weed control in container plant production.

Survey of Reclaimed and Non-reclaimed Irrigation Water Use for Production of Container-grown Plants in Florida

A descriptive survey was conducted of container plant growers using reclaimed water (processed sewage) for irrigation of nursery crops and growers whose businesses were located in areas where reclaimed water was available but not used for irrigation. Surveys were completed during site visits except when participants wanted to complete the survey at a later time. Nurseries using reclaimed water produced trees, shrubs, perennials, bedding plants, foliage plants, and potted flowering plants. Average area outdoors or under shade irrigated with overhead sprinklers was 3.5 ha (8.6 A) and 10,777 m2 (116,000 ft2) for greenhouses. Participants responded that reclaimed water quality (67%) and quantity (50%) were consistent over time. All reclaimed water users were satisfied with both quality and quantity of reclaimed water. Most growers (83%) not using reclaimed water were using well water as the primary source of water. Seventy-one percent of non-reclaimed users responded that expense of connection to reclaimed water was a limitation, while 57% indicated that unknown water quality and health or safety concerns were limitations. Results from this survey indicated acceptance of reclaimed water among active users and the need for education about reclaimed water for non-reclaimed users.