Tips For Growing Cauliflower (Including Fall Trial, 2015) Daniel Becker Vegetable and Small Fruit Extension Associate Department of Horticulture, University of Kentucky Cauliflower: Background Cole crop very closely related to broccoli, but also cabbage, B. sprouts, collards, kale, etc. All members of species Brassica oleracea Belong to mustard family (Cruciferae) Originated in maritime areas of Europe, including Mediterranean and Asia Minor Believed that it originated from broccoli Confusion about classification in past Grown for edible head called a curd Highly branched, pre-floral organ Photo courtesy: geograph.org.uk Cool Season Crop Optimum mean temp. for head formation is 57-68 F Above 68 F quality is poor Above 77 F often no heads Hardy plants that can handle a light to moderate freeze Vegetative: 22-24 F Mature (once heads form): 25-28 F After 21.8 F Best Conditions for Growth Uniformly cool temps. best for growth and quality Requires exposure to cool weather for curd production Due to evolving from wild cabbage (biennial) Early maturing types require shorter periods* Too much heat will reduce head development Performs poorly when grown as a spring crop Rapid warming and variable weather conditions Cool cond. just too short to mature crop Most varieties 70 d. maturity *Does best as a fall crop* Temperatures more consistently cool Conditions are drier Ease of field working/planting *Preferred type for fall growing in east Fertility and Soil Requirements Does best when grown on fertile, well drained loam soils High requirement of micronutrients All except N pre-plant incorporated Disk soil, spread evenly, then till-in Heavy feeder of boron Low in most Midwest soil Apply 2-3 lb boron/acre with preplant 6.0-6.5 ph below 5.5 molybdenum deficiencies occur Whiptail leaves, poor plant growth Apply lime to increase ph + 0.5 lb sodium molybdenate/acre If soil above 6.8 ph sulfur deficiencies can occur, add 10-20 lb actual S/acre Soil Test Results (lb/a) 1 Phosphorous Fertilizer Needed (lb/a) Phosphate (P2O5) Low 31 121-180 Medium 31-60 61-120 High 61-80 31-60 Very High 80 0-30 Potassium Boron deficiency causes hollow stem, also due to excess N Potash (K2O) Low 201 101-150 Medium 201-300 51-100 High 301-450 1-50 Very High 450 0 1 Information from 2015-16 Vegetable Production Guide for Commercial Growers. University of Kentucky Cooperative Extension, ID-36. Photo courtesy: Carl Rosen, University of Minnesota Nitrogen (N) Pre-plant Broadcast and incorporate 50 lb actual N/acre Can be in rows/prepared beds if known where plants will be set When heads start forming Side-dress with 50 lb actual N/acre Repeat at same rate two weeks later Or fertigate every 7-10 days with 10 lb actual N/acre starting 4 weeks after transplanting 6 total applications Usually 100 lb actual N/acre is all that is needed during growing season If tip burn* has been a problem in past use calcium nitrate Photos courtesy: Carl Rosen, University of Minnesota Nitrogen deficiency *Tip burn caused by calcium deficiency - due water stress from uneven soil moisture - make sure adequate and even watering occurs - check soil ph (6.0-6.5) 1
Seeding and Seedling Care Plant seeds into trays at least 4-6 weeks before transplanting May 20 to June 5 south central IL June 1 to June 15 far southern IL 1/2 to 3/4 inch deep (dull pencil) 50-98 cell trays (2-3 inch depth, 1.25-2 inch top) Smaller: weak plants Larger: wasted media Fill trays only with seedling media Drains well, don t use garden soil Water as needed until media wetted or 1-2 times daily Less needed earlier More and more often as seedlings grow (2-3 times/day) Seeding and Seedling Care Very sensitive to low light (full or partial sun best) Moderate fertilizer starting 1-2 weeks after emergence 1-2 week intervals Helps in seedling growth 3-4 tsp/gal. water soluble fertilizer Keep an eye on cabbageworms! Quickly defoliate, eat growing point Carbaryl (Sevin) at 2 tsp/gal. When it becomes difficult to keep plants watered Morning watering: semi-wilted by mid-day Good indication that it is time to transplant Transplanting 4-6 weeks after seeding June 20 to July 20 south central IL July 1 to July 30 far southern IL Make sure field is well tilled Makes easier to form beds if using plastic May apply pre-emergent herbicide Plant early in morning on cloudy day (reduces water loss) Space plants 18 inches apart in the row Rows spaced at least 36 Inches apart Cover root ball with at least 1/4 inch of soil Water-in immediately to close soil and eliminate air pockets Can mix 3-4 tsp/gal. as starter fertilizer using 1/2 pint ( 1 cup)/plant Watering For good growth and productivity Require even and consistent soil moisture About 1 inch of rainfall per week Weekly supplemental irrigation is required If rainfall less than 1 inch Usually during June-September Best way for large plantings is using drip tape 8 or 12 inch emitter spacing 0.5 or 0.45 GPM/100 ft About 9 hrs of watering required per acre to reach 1 inch 13,000 gal for 48 inch row spacing Need 1/2 this if 1/2 inch rainfall Attach to blue lay-flat or orchard tubing Run 2-3 inches away from row or base of plant (reduces pooling) Water sources: well, pond (must filter), municipal (expensive!) Photo courtesy: Aqua Traxx Imported and Cross striped cabbageworms Insect Control Subject to many damaging insect pests Begin scouting after seeds emerge Holes in leaves Honeydew, sooty mold under plant 7-10 day spray schedule Organic: Bt, pyrethrum, insecticidal soap Conventional: Carbaryl (Sevin), Organophosphate (Malathion), Pyrethroid (Mustang Max) Read and follow labels PPE s, REI s, and PHI s Rotate to prevent resistance Cabbage loopers Aphids Photos courtesy: Zachary Boone Snipes and Clemson University Cooperative Extension Alterneria leaf spot Black rot Disease Control Cultural: clean seed, well drained site, weed control, residue removal, rotation Begin scouting after the seeds emerge Spotting on leaves Lesions, necrosis Sudden or prolonged plant collapse 7-10 d. spray interval (can be mixed with insecticides) Clorothalonil (Bravo), fixed copper (Kocide), maneb (Mancozeb etc.) pyraclostrobin (Cabrio) Read and follow labels PPE s, REI s, and PHI s Rotate to prevent resistance Photos courtesy: Zachary Boone Snipes and Clemson University Cooperative Extension Root rot, yellow wilt, wire stem, damping-off (Phytophthora, Fusarium, Rhizoctonia, Pythium) Downy Mildew 2
Weed Control Compete for water, nutrients, and space Alternate hosts for insects and diseases Remove from site before transplanting Tilling, pre-emergent: Carfentrazone (Aim) napropamide (Dacthal), oxyfluorfen (Goal) After transplant Some pre-emergent s can be used: Dacthal Post-emergent s: Sethoxydim (Poast for grasses), Paraquat (Gramoxone), Glyphosate (Roundup be careful of drift!) Keep weed free area around plant: plastic mulch, organic mulch (straw), shallow cultivation Cover cropping in aisle Can be planted at same time as crop Till soil, spread seed by hand, rake to cover 50-100 lb/acre annual rye, wheat, oats Read and follow labels: PPE s, REI s, and PHI s Spray tank specially set aside for herbicides! Tying Exposure to sunlight discolors curds, turning them yellow Edible but unmarketable Tying blanches curds, keeping white Pull back leaves, inspect plants center 10 days before advertized maturity Tie when curds reach 3-4 inches in diameter (size of soft ball) Wrap 8-12 leaves around head, tie high and loose Reduces humidity and molding Colored rubber bands makes job easy Record date by band color Gives clue about when to harvest Begin 7-10 days after tying Curds 6-8 inches in diameter Depends upon weather (colder = longer) Don t let them get overripe Become loose or ricey (individual florets emerge) Cut curds with 3-4 whorls (6-8 actual) of leaves attached Trim leaves back enough to circle and protect curd To just above the point where the curd is widest If not used immediately, store at 32 F and 90% humidity Photo courtesy: USDA Fall Trial, 2015 Seeding June 5 Seedling fertilizer Insecticide Layout and Management 50 cell trays Berger BM-2 germinating mix Watered daily: automated, 2 times(morning and evening), 7 min. 4 tsp./gal. Miller s Sol- U-Gro (11-48-8), weekly 2 tsp./gal. Sevin XLR Plus (cabbage worms), 10 day interval Layout and Management Transplanted August 10 Plant spacing (inrow) x row spacing Fertilizer Trickle irrigation Pesticide and 18 inches x 5 feet Cauliflower: October 16 November 24 (killing freeze Nov. 23: 21.8 F) Brussels sprouts: November 13 December 23 Pre-plant: following soil test recommendation Fertigation: 10 lbs. actual NPK/A of 20-20-20 every 10-14 days (6 applications, 60 lb total NPK/A) As needed Following recommendations of ID-36 and USDA grading standards 3
Cauliflower Management Plants inspected weekly once heading started Walked field, pulled leaves back, checked for developing stems Started about 10 days before advertised harvest period Wrapped when heads reached baseball size, about 3-4 diam. Tied high as possible to promote circulation, reduce molding ed 7-10 days later, based upon weather (temperature, rainfall) 20 cultivars 19 white, 1 green Cauliflower Data Days to harvest Total marketable yield/a Heads/A Average head weight Head diameter Curd color, compactness, doming, riciness, fuzziness Wrapping (self-blanching) All cultivars leaves banded regardless of advertised self-wrapping ability Rated immediately before harvest based upon coverage of wrapper leaves Means separated by Tukey s Studentized Range HSD Test (P 0.05). Means followed same letter are not significantly different, those without letters are also not significantly different. Cauliflower Data: 1-5 Rating Generally: 1 = poor; 5 = excellent Wrapping Wrapping: 1 = none; 2 = slightly; 3 = partially; 4 = mostly; 5 = fully Curd color: 1 = yellow-green (or off-colored); 2 = yellow; 3 = light yellow; 4 = creamy white; 5 = white Curd compactness: 1 = very loose; 2 = loose; 3 = moderate; 4 = compact; 5 = very compact 1 = none 4 = mostly 2 = slightly 3 = partially Curd doming: 1 = sunken; 2 = flat; 3 = low; 4 = moderate; 5 = high 5 = fully Riciness, Fuzziness: 1 = very heavy; 2 = heavy; 3 = moderate; 4 = light; 5 = none Curd Color Riciness: 1 = very heavy 5 = white 3 = light yellow 4 = creamy white 2 = yellow Comp.: 1 = very loose Riciness, Fuzziness, Compactness, and Mold Fuzzi.: 1 = very heavy 1 = yellow-green, off colored Downy mildew 4
Seed Source Advertised Days to (Catalogue) Observed Days to Steady Seedway 67 72-95 Flamenco Seedway 71 72-95 Aquarius Stokes 70 84-106 Synergy Rupp 79 95-106 Argos Seedway 80 95-106 Artica Stokes 75 95-106 Apex Stokes 71 95-106 Absolute Seedway 75 95-106 Terzolo Seedway 62 67-92 Casper Stokes 76 95-106 Freedom Rupp 67 72-95 Incline Rupp 76 95-106 Cumberland Stokes 76 95-106 Denali Johnny s 73 92-101 Basan Seedway 75 95-106 Altamira Seedway 86 95-106 Amazing Seedway 75 84-101 Fargo Seedway 90 95-106 Skywalker Johnny s 80 84-106 Panther (green) Seedway 76 95-101 Mrktbl. Yld. (lb/a), 5808 pl./a Heads (No/A Avg. Head Wt. (lb) Head Diameter (in) Steady 19,846 a 5,663 3.4 a 7.6 a Flamenco 19,094 ab 5,518 3.3 ab 7.4 ab Aquarius 18,868 abc 5,663 3.2 abc 6.7 abc Synergy 17,926 abcd 4,791 3.1 abcd 6.9 abc Argos 17,678 abcd 5,227 3.0 abcd 6.9 abc Artica 17,115 abcde 5,372 2.9 abcde 6.6 abc Apex 16,801 abcde 5,663 2.9 abcde 6.8 abc Absolute 16,801 abcde 5,663 2.9 abcde 6.7 abc Terzolo 16,426 abcdef 5,518 2.8 abcdef 6.9 abc Casper 16,141 abcdef 5,518 2.8 abcdef 6.3 cd Freedom 16,006 abcdef 4,792 2.8 abcdef 6.9 abc Incline 15,646 abcdef 5,663 2.7 abcdef 6.7 abc Cumberland 14,954 bcdef 5,227 2.6 bcdef 6.2 cd Denali 14,870 bcdef 5,518 2.6 bcdef 6.3 cd Basan 14,128 cdefg 5,227 2.5 cdefg 6.3 cd Altamira 13,796 defgh 5,227 2.4 efgh 6.1 cde Amazing 12,524 efgh 5,518 2.3 efgh 6.5 bcd Fargo 11,921 fgh 5,518 2.2 fgh 5.6 de Skywalker 9,443 gh 4,464 1.7 gh 5.2 e Panther (green) 9,300 h 5,518 1.6 h 6.0 cde Wrapping Curd Color Curd Compactness Curd Doming Riciness, Fuzziness Steady 2.6 fgh 4.7 ab 4.6 abc 4.9 ab 4.4 abc Flamenco 2.4 gh 4.4 ab 4.5 abc 4.8 ab 4.3 abc Aquarius 3.8 abcde 4.5 ab 4.5 abc 4.9 ab 4.4 abc Synergy 3.8 abcde 4.5 ab 4.6 abc 4.8 ab 4.5 abc Argos 4.1 abc 4.7 ab 4.6 abc 4.9 ab 4.2 bcd Artica 3.8 abcde 4.7 ab 4.5 abc 4.8 ab 3.7 de Apex 3.7 bcde 4.5 ab 4.4 bc 4.8 ab 4.5 abc Absolute 3.1 efg 4.5 ab 4.2 c 4.8 ab 4.1 dc Terzolo 2.1 hi 4.3 ab 4.9 a 4.9 ab 4.6 abc Casper 4.5 a 4.8 a 4.8 ab 4.9 ab 4.8 a Freedom 2.8 gf 4.6 ab 4.8 ab 4.9 ab 4.4 abc Incline 3.2 defg 4.5 ab 4.6 abc 4.8 ab 3.5 e Cumberland 3.9 abcd 4.4 ab 4.6 abc 4.8 ab 4.6 abc Denali 3.9 abcd 4.7 ab 4.6 abc 4.9 ab 4.5 abc Basan 3.9 abcd 4.6 ab 4.6 abc 4.9 ab 4.4 abc Altamira 3.4 cdef 4.7 ab 4.4 abc 4.8 ab 4.5 abc Amazing 1.5 i 4.2 b 4.7 ab 4.9 ab 4.2 bcd Fargo 4.2 ab 4.2 b 4.7 ab 4.8 ab 4.1 cd Skywalker 4.1 abc 4.3 ab 4.5 abc 4.6 b 4.2 bcd Panther (green).. 4.4 abc 5.0 a 4.7 ab What s the Take-Home Message Take advertised days to harvest with a grain of salt Seasons and growing sites vary, so do plant development rates Expect harvest to last 20-25 days (3 weeks) with 3 to 4 pickings Steady and Flamenco had highest yields (1 st, 2 nd ), 72-95 d. Later ripening: try Aquarius and Synergy (3 rd and 4 th ), 84-106 and 95-106 d. Best self wrapping cultivar was Casper (10 th ), but Argos (5 th ) had similar ratings (4.5 vs. 4.1) with 9% greater marketable yield (16,141 vs. 17, 678 lb) No cultivar in trial was entirely fully self-wrapping (Casper and Argos ranged from 3 = partially to 5 = fully) Rubber bands are still a useful tool Keep an Eye on Those Self- Wrapping Types! Brussels Sprouts Production (Including Fall Trial, 2015) Daniel Becker Vegetable and Small Fruit Extension Associate Department of Horticulture, University of Kentucky 5
Background and Best Growth Conditions Cole crop just like cabbage, cauliflower, and broccoli Originated in northern Europe, around Brussels, Belgium Form of non-heading cabbage Grown for buds formed along stem Cool season crop Requires uniformly cool temps. and even soil moisture for best growth Optimum: average of 60-65 F, maximum 75 F above which quality is poor Very hardy: can withstand 20 F Performs poorly when grown as a spring crop Warms too rapidly to mature crop Requires long growing periods: most varieties 90 day from transplant to maturity *Does best as a fall crop* After 21.8 F Fertility and Soil Requirements Has the same fertility recommendations as for Cauliflower Amend soil pre-plant if deficient (P, K, B, Mo, S) 6.0-6.5 ph best (if more alkaline 6.8, amend with sulfur) Nitrogen 50 lb pre-plant Another 50 lb, 6 weeks after transplant and again 4 weeks later Or fertigate every 7-10 days with 10 lb actual N/acre starting 4 weeks after transplanting 7 total applications Usually 100 lb actual N/acre is all that is needed during growing season Soil Test Results (lb/a) 1 Phosphorous Fertilizer Needed (lb/a) Phosphate (P2O5) Low 31 121-180 Medium 31-60 61-120 High 61-80 31-60 Very High 80 0-30 Potassium Potash (K2O) Low 201 101-150 Medium 201-300 51-100 High 301-450 1-50 Very High 450 0 1 Information from 2015-16 Vegetable Production Guide for Commercial Growers. University of Kentucky Cooperative Extension, ID-36. Seeding and Seedling Care Same general suggestions as cauliflower May 20 to June 5 south central IL June 1 to June 15 far southern IL Varieties longer than 100 day maturity should be started earlier 50-98 cell trays (2-3 deep, 1.25-2 top) filled with seedling media Water as needed until media wetted or 1-2 times daily (less earlier, more later) Plants are very sensitive to low light (easily become leggy) Best to use mist watering, heaver than this and plants tend to fall over Don t water too much (very susceptible to wire stem, damping-off) Fertilize and spray for cabbageworms similar to cauliflower 3-4 tsp/gal. water soluble fertilizer Carbaryl (Sevin) at 2 tsp/gal. Transplanting and Watering 4-6 weeks after seeding June 20 to July 20 south central IL July 1 to July 30 far southern IL 100 d. varieties should be planted earlier Plant into tilled or plastic covered beds, in morning on cloudy day Space plants 18 in-row and at least 36 between rows Cover with 1/4 inch of soil and water immediately Weekly supplemental irrigation required If rainfall less than 1 (usually June-Sept.) Use drip tape: 8-12 emitter spacing 0.45-0.5 GPM/100 ft (lay flat or orchard tubing) 9 hrs of watering req./acre to reach 1 Water sources: well, pond (must filter), municipal (expensive!) Imported cabbageworm Cross striped cabbageworm Aphids Pest and Weed Control Seedlings emerge = begin scouting Look for damaged leaves, infection Begin 7-10 day spray schedule Use appropriate chemicals Read and follow label directions Be aware of PPE s, REI s, PHI s Rotate to prevent infections Use good cultural practices Clean seed, well drained, control weeds, remove residue, rotation Weed free area around plant Plastic mulch, straw, cultivation Pre-emergent and post-emergent herbicides (careful of drift) Can use cover crops in aisle (hand spread 50-100 lb/acre) Cereal rye, wheat, oats Photos courtesy: Zachary Boone Snipes and Clemson University Cooperative Extension Downy Mildew Damping-off, etc. Cereal rye cover crop Topping Strategy used for commercial (once-over) harvest of whole stalks Promotes maturity (increased size) of small sprouts at top of stem Avoids Christmas tree shape: big sprouts on bottom with progressively smaller sprouts towards top of stem Remove top 1 inch of stem 30 days prior to expected harvest (using hand shears) Need to know transplanting date and maturity period (Julian days) of variety Ex.: A 95 day maturing variety transplanted on 10 Aug. (J.D. 222) Topped 65 days later on 15 Oct. (J.D. 287) 30 days after on 13 Nov. (J.D. 317) Topping is not necessary if individual sprouts are harvested 6
Done when sprouts have reached desired size (usually 1-1.5 in diam.) Once-over whole stem Using loppers to cut at base of stem Remove leaves by stripping with hand outside of the field Cut off any part of stem and sprouts that are too large or too small Individual sprouts Break away leaves around sprouts to be harvested Working from bottom upward cut off sprouts as they develop in size A note about leaf removal Removal from plant prior to harvest negatively impacts growth Does not encourage sprout formation Robs plants of energy = smaller, weaker growth Fall Trial, 2015 Seeding June 5 Seedling fertilizer Insecticide Layout and Management 50 cell trays Berger BM-2 germinating mix Watered daily: automated, 2 times(morning and evening), 7 min. 4 tsp./gal. Miller s Sol- U-Gro (11-48-8), weekly 2 tsp./gal. Sevin XLR Plus (cabbage worms), 10 day interval Layout and Management Transplanted August 10 Plant spacing (inrow) x row spacing Fertilizer Trickle irrigation Pesticide and 18 inches x 5 feet Cauliflower: October 16 November 24 (killing freeze Nov. 23: 21.8 F) Brussels sprouts: November 13 December 23 Pre-plant: following soil test recommendation Fertigation: 10 lbs. actual NPK/A of 20-20-20 every 10-14 days (6 applications, 60 lb total NPK/A) As needed Following recommendations of ID-36 and USDA grading standards Management Transplant date recorded (August 10) Plants topped 30 days from harvest date (indicated by seed catalogues) Topped by removing apical growing point by cutting Leaves were not pulled from around developing sprouts Whole stalk harvested on recommended date Plants cut at base with loppers Leaves removed from stalk outside of trial field date varied 2-6 days (post rec. day), depending upon weather and weekday (Saturday, Sunday excluded) One-and-then-done harvest Brussels Sprouts Data 16 cultivars (15 green, 1 red) Total marketable stem yield/a Marketable stems/a Average marketable stem weight Marketable stem length Sprouts between 1 and 1 ½ inch in diameter Unmarketable stem length Sprouts less than 1 inch or greater than 1 ½ inch in diameter, or too loose Total Stem Length Total marketable sprout yield/a No. sprouts/stem Average sprout weight Sprout compactness (judged by compression between thumb and forefinger) 1 = very loose; 2 = loose; 3 = moderate; 4 = compact; 5 = very compact Perception of bitterness rating (cooked 40 minutes at 400 F) 1 = very high; 2 = high; 3 = moderate; 4 = slight; 5 = none Means separated by Tukey s Studentized Range HSD Test (P 0.05). Means followed same letter are not significantly different, those without letters are also not significantly different. 7
Few Sprouts Loose Sprouts Compact Sprouts Seed Source Days to (Catalogue) Marketable Stem Yield (lb/a) Marketable Stems (No/A) Average Marketable Stem Weight (lb/a) Jade Cross E Stokes 95 8,821 a 5,001 ab 1.8 a Dimitri Seedway 105 8,181 ab 5,324 ab 1.5 ab Cobus Stokes 130 6,153 abc 5,808 a 1.1 bc Franklin Seedway 100 5,904 abc 5,001 ab 1.2 bc Dagan Seedway 100 5,797 bcd 4,840 ab 1.2 bc Churchill Johnny s 90 5,655 bcd 5,163 ab 1.1 bc Hestia Seedway 100 5,442 bcd 5,001 ab 1.1 bc Divino Seedway 100 4,908 cd 4,517 ab 1.1 bc Aurelius Stokes 140 4,837 cd 5,163 ab 0.9 cd Gustus Stokes 120 4,659 cd 4,679 ab 1.0 bcd Diablo Johnny s 110 4,019 cd 5,324 ab 0.8 cd Nelson Rupp 90 3,984 cd 4,840 ab 0.8 cd Nautic Johnny s 105 3,735 cd 4,033 b 0.9 cd Long Island Imp. Rupp 100 2,881 de 1,613 c 1.8 a Red Ball Seedway 120 391 e 807 d 0.5 d Catskill Imp. Seedway 95... Marketable Stem Length (in) Unmarketable Stem Length (in) Total Stem Length (in) % Marketable Stem (of Total) Jade Cross E 10.1 ab 3.8 f 12.9 def 76.6 a Dimitri 10.7 a 8.9 bcd 18.8 ab 56.0 cde Cobus 9.9 ab 9.2 abc 19.2 a 51.8 def Franklin 9.1 abc 5.6 def 13.9 de 64.6 bc Dagan 9.9 ab 6.2 cdef 15.0 cde 64.5 bc Churchill 9.3 abc 5.9 cdef 14.2 de 65.6 abc Hestia 7.4 bc 8.1 cde 14.7 cde 49.2 ef Divino 7.7 abc 5.2 ef 11.7 ef 61.2 bcd Aurelius 7.8 abc 8.5 cde 15.9 abcd 48.6 ef Gustus 7.8 abc 8.8 bcd 15.3 bcd 46.3 ef Diablo 6.4 cd 8.4 cde 14.4 de 43.7 f Nelson 7.7 abc 7.3 cde 14.3 de 52.7 def Nautic 8.2 abc 12.4 a 18.3 abc 44.8 ef Long Isl. Imp. 8.4 abc 7.4 cde 9.8 fg 70.9 ab Red Ball 3.5 d 11.9 ab 13.2 def 27.7 g Catskill Imp.. 6.2 cdef 6.2 g. Tot. Mrktbl. Sprout Yld. (lb/a) # Sprouts/ Mrktbl. Stem Avg. Sprout Wt. (oz) Sprout Comp. Bitter. Comments Jade Cross E 4,741 ab 42.0 ab 0.35 bc 4.8 ab 4.3 Stems with closely spaced sprouts, very low bacterial leaf spot incidence Dimitri 5,177 a 35.7 bc 0.40 ab 4.7 ab 4.3 Long stems with widely spaced sprouts, very low bacterial spot incidence Cobus 3,153 cd 27.0 d 0.32 bc 4.7 ab 4.2 Long stems with widely spaced sprouts Franklin 3,785 bcd 29.7 cd 0.40 ab 4.0 bcd 4.0 Moderate bacterial leaf spot incidence Dagan 3,283 dc 28.4 d 0.39 ab 3.5 d 4.5 Uneven (loose) sprout development Churchill 3,680 bcd 27.7 d 0.38 abc 4.0 bcd 4.7 Plants tend to produce suckers Hestia 3,990 abc 25.6 de 0.48 a 3.6 cd 4.3 Uneven (loose) sprout development, moderate bacterial leaf spot incidence Divino 3,177 cd 26.2 d 0.39 ab 4.2 abcd 3.7 Moderate bacterial leaf spot incidence Aurelius 3,294 bcd 25.2 de 0.39 ab 4.8 ab 4.0 Plants tend to lean Gustus 3,106 cd 24.8 dc 0.40 ab 4.4 abcd 4.0 High bacterial leaf spot incidence Diablo 2,643 cde 19.0 e 0.38 abc 4.0 bcd 3.7 High bacterial leaf spot incidence Nelson 2,338 de 23.8 de 0.33 bc 3.7 cd 3.8 High bacterial leaf spot incidence, uneven (loose) sprout development Nautic 2,409 de 23.5 de 0.38 abc 4.5 abc 4.3 Plants tend to lean Long Isl. Imp. 1,334 ef 42.9 a 0.28 bc 5.0 a 4.0 Uneven stem formation Red Ball 116 f 9.1 f 0.26 c 4.0 bcd 4.0 Poor stem/sprout development Catskill Imp...... Plants did not form stems/sprouts 8
Bacterial Leaf Spot (Pseudomonas Syringae pv. maculicola) Primarily seedborne, but also in crop residue and soil Affects cole crops: cauliflower, broccoli, Brussels sprouts Water soaked lesions Brown or purple coloration Often affect entire sprout (don t remain on surface) Prefers cool, wet weather Control Chemical: none proven effective (copper?) Cultural: use clean seed, avoid overhead irrigation, remove debris, rotate crops What s the Take-Home Message Days to harvest listed on seed packets are pretty accurate predictor Provide good guide of when to top plants Topping 30 d. to harvest worked well (vs. 60 d.) 1 Final decision to harvest should be based on sprout development Jade Cross E and Dimitri had the highest stem and sprout yields Also produced greatest marketable stem length Jade Cross E had greatest % of marketable stem Hestia had largest sprouts but also was one of the least compact (opposite of Long Island) Little difference in bitterness (cooked) detected May be due to mild weather during harvest? 1 Sideman, Becky and Olivia Saunders. Brussels sprouts variety trial and topping study, 2013 & 2014. University of New Hampshire Cooperative Extension. http://extension.unh.edu/resources/resource/3914/brussels_sprouts Trial_and_Topping_Study_2013/2014. Accessed July 23, 2015. Not Everyone Likes Brussels Sprouts Thanks! June Johnston, Virginia Travis, and Dr. Winston Dunwell for help with planting, management, harvest, and data collection Dwight Wolfe for planting and with data processing But voles sure do! Seedway, Stokes, Rupp, and Johnny s for providing seed Elizabeth Wahle for inviting me Cited: ID-36, Vegetable Production Guide for Commercial Growers UK Cooperative Extension Service 9