2014- The Year of Cucurbits!

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All in the family… Cucumber Summer squash Winter squash Pumpkin Muskmelon and cantaloupe Watermelon Gourds These are all members of the plant family Cucurbitaceae and are referred to as “cucurbits.”

Reasons to grow cucurbits Easy to grow from seed Lots of different types and cultivars Some can be stored and eaten over the winter Versatile in the kitchen But monitor them closely because they are susceptible to many insect pests and diseases.

Planting tips Full sun location- 6-8 hours of direct sunlight. 6-8 in. of loose, fertile soil. Plant after Mother’s Day when the soil has warmed and the danger of frost is passed. Cover seedlings with floating row cover to speed up growth and protect plants from pests. Thin out seedlings so that you end up with the correct spacing between plants.

Fertilizing tips Cucurbits have a moderate need for nutrients compared to other vegetable crops. Add 1 inch of compost each year to contribute to long-term nutrient reservoir. Nitrogen is nutrient most often in short supply. Fertilize at planting or flowering with one of the “meals” (kelp, fish, cottonseed, alfalfa.) Over-fertilization can burn plants or stimulate excessive leaf growth at the expense of fruit.

Sex and the cucurbit

Cucurbit flower structure

Wanted: native bees; must be able to lift and transport pollen from male to female flowers (we also welcome European honeybees)

CROPTYPE OF FLOWER OPEN BLOOM PERIOD # OF BEE VISITS NEEDED COMMENTS Pollination Requirements Summer squashImperfect/moneci ous 6 hrs.; dawn- noon 8-12Male flowers open and close 30 min. earlier than female flowers. Pumpkin/winter squash Imperfect/moneci ous 6 hrs.; dawn- noon 8-12 MuskmelonPerfect, self-sterile and imperfect male flowers 8am-dusk12Stigma receptive to pollen grains for only a few hrs. early in morning. WatermelonImperfect/moneci ous 8am-dusk8-10Seedless cultivars require pollination to set fruit; then seeds abort. CucumberImperfect/moneci ous 8am-dusk8-12Staminate flowers usually appear 10 days before pistillate flowers

Frequent (but temporary) problems: failure to set fruit and dropped fruit. Causes: Male and female flowers not open at the same time Lack of pollinators due to cold, wet weather, pesticides, and habitat loss (ovary is not fertilized) Plants are over-fertilized, spaced too closely; low sunlight Deformed fruits- shrunken or tapered at one end- are caused by poor pollination; too few bee visits or failure of pollen to fertilize ovules (seeds).

Deal with weeds or they will ruin your garden!

Weed management Weeds are plants that thrive in disturbed soil. Best control methods: – crop cover (fast growing cucurbits) – hand-pull – sharp hoe – mulch Other organic methods (not recommended): vinegar, flame weeder, commercial herbicidal soap.

Organic mulches Prevent weed growth; add to soil organic matter. Moderate soil temperatures; conserve soil moisture. Can provide habitat for pests along with beneficial critters. Examples: grass clippings, newspaper covered with straw, shredded leaves, compost

Synthetic mulches Black plastic mulch warms the soil for earlier, higher yields of warm-season crops, like melons. Landscape fabric warms soil the soil and is permeable air to water. Can be re-used.

Drip irrigation: saves time and water

Growing up: using vertical space Increase yields per sq. ft. Fewer fruit problems; easier to pick, water, and spray. Adds complex texture to garden; use shaded side for lettuce and spinach

Cucumbers (Cucumus sativus) Native of India, cultivated for more than 3000 years Slicing or pickling type fruits – Burpless – thin, more tender skin; milder flavor Plant types: bush or vining – Vining requires trellising Days to maturity: – Picklers mature more quickly Do not do well in clay soils – Work in 2-3” compost prior to planting – Fertilize at blossom, and 3 weeks later 18 GE 108: Cucumbers

Cucumbers Plant ½” deep, 4” apart in rows 4 feet apart – Or plant 6 seeds on hills spaced 3 feet apart – Thin to 6-12” apart in rows, or 3 plants per hill Can plant small batches every 2-3 weeks until late June Keep evenly watered, particularly when forming fruit to prevent bitterness Overripe cucumbers become bitter and seedy 19

Melons (Cucumis melo) muskmelons In Eastern U.S. most cantaloupe are muskmelons – Rough skin (netting); fruits “slip” from stem Honeydew, casaba, crenshaw melon can also be grown Plants seeds 1” deep, 2-3 feet apart in rows 6 feet apart; or in hills spaced 3 feet apart with 3 seeds per hill Climbing vine, not suitable for small gardens 20 GE 115: Muskmelon 2010

Melons For early harvest, start seeds inside 3-4 weeks prior to transplanting Can be hand pollinated Like moist soil and are medium feeders – Fertilize at fruit formation Maturity: days; if grown in trellis, the fruits must be supported Harvest when stem separates easily at the point of attachment 21

‘Minnesota Midget’ above ‘Tigger’ below

Watermelon (Citrullus lanatus) Native of Africa; mature fruits can weigh up to 200 pounds! Vine not climbing but takes a lot of ground space! Seedless varieties require a seeded variety nearby for pollination Plants seeds 1” deep, 2-3 feet apart in rows 6 feet apart – Or grow in hills spaced 3 feet apart with 3 seeds per hill Seed outside in mid-May – Can also start indoors 3-4 weeks earlier Mature in days from seeding 23 GE 130: Watermelon 2011: this is only 1 plant!

Watermelon Fertilize when vines begin to run and at 1 st fruit set Need an inch of water per week at the beginning – Stop watering when the fruits begin to ripen Harvesting: – Tendrils will turn brown and dry – Green color is less bright – Skin will be resistant to thumbnail penetration – Rind on the underside of the melon will turn from white to pale yellow 24

Watermelon, Japanese style

‘Yellow Moon & Stars’, an heirloom cultivar Audra Russell, UME Master Gardener, with impressive harvest Watermelon’s distinctive lobed leaves

Summer squash (Curcubita pepo) American natives, known for their abundance in the backyard garden – August 8: “National Sneak Zucchini on your Neighbor’s Porch Day” Can be: green (zucchini), yellow (straight or crookneck), white (scalloped or pattypan) – Round or oblong varieties Large plant: bush or vining types 27 GE 125: Summer Squash

Summer squash In mid-May plant 5-6 seeds in hills 3 feet apart and thin to 3 plants per hill, or plant 2-3 feet apart in rows 2-3 feet apart Can plant as late as mid-July (Central MD) Medium feeders: fertilize 4 weeks after blossoming male flowers to appear 1-2 weeks before female Possible to hand-pollinate for more fruiting 28

Summer squash Harvest when fruits are 6-8 inches long – ‘Baseball bats’ will become spongy and seedy Round or scalloped types are best at 3-4” diameter Flowers are edible – great in salads! Great in soups, baked, fried – Also in PIE!!! 29

Yellow straightneck squash Scallop or patty pan squash Zucchini fritters or bread anyone?

Prevent fruit rot disease by removing blossoms from enlarging fruit. Natural color pattern in zucchini leaves.

Winter squash (Curcubita spp.) Some are the same species as summer squash (Cucurbita pepo), but harvested and eaten at mature stage – Skin toughens into hard, inedible rind – Great source of beta carotene, Vitamin C, and potassium Lots of fun shapes and sizes, including: Vining plants take a lot of space Mature in days from seed 32 GE 131: Winter Squash Immature spaghetti squash ButternutAcornSpaghettiPumpkinGourd

Winter squash Plant 2-3 seeds every 3-4 feet in rows 8-12 feet apart; can also grow in hills 3-4 feet apart Fertilize at planting and again 3 weeks after blossoming begins Can hand-pollinate Prop pumpkins off ground to prevent rotting 33

Winter squash Harvest when rinds are hard and firm – Use sharp knife to cut stem, leaving 2” to prolong storage Store winter squash in a cool dry area, like a basement – Store in single layer without touching to discourage rot diseases Preparation: peeled, diced, and roasted; pureed in soups; roast the seeds! 34

Spaghetti squash above and butternut squash below.

So many kinds of winter squash and pumpkin! Cheese pumpkin

‘Tromboncino’ squash

‘Cucuzzi’ gourd (white flower) The vines grew up into this gardener’s trees. Fruit elongate rapidly and are tender at 4 ft. in length.

Mouse melon Cherry tomatoMouse melon

Organic Integrated Pest Management (IPM) Organic pesticides are a last resort Planting to provide nectar and pollen for beneficial insects (including pollinators ) mountain mint, anise hyssop, thyme, oregano, basil, dill, yarrow, aster, marigold, zinnia, alyssum, phlox, bee balm, milkweeds, butterfly weed, borage, salvias, lamb’s ear

Biological control Give mother nature a chance! – Predators eat pests – Parasitoids lay their eggs on or in pests

Natural predators Lady beetle larva Orb-weaver spider Assasin bug

Tiny, non-stinging wasp parasitoid inserting eggs into aphids. The wasp larvae hatch out and eat the aphids from the inside.

Floating Row Covers First line of defense against frost- spring or fall Hastens germination Protection for tender plants/seedlings from heat/sun Excludes pests ‘Hold-ups’ (support); examples: pvc pipe, reinforcing wire, and nine gauge wire few; be creative!

Enviromesh protects crops from insects and wildlife. Floating row cover supported by #9 wire above and pvc pipe below.

Some effective organic insecticides Pyrethrins- controls or suppresses a wide range of insects (Pyganic- 1.4%) Neem extract – suppresses beetles and caterpillars Neem oil- insecticide and preventative fungicide Spinosad- controls beetles, caterpillars, flies, thrips

Some effective organic insecticides (cont.) Bacillus thuringiensis- controls young caterpillars; suppresses large caterpillars Surround- controls aphids, mites, caterpillars; suppresses bugs Hort oil- controls aphids, mites, soft-bodied immatures Insecticidal soap- suppresses aphids, mites, soft-bodied immatures

Spotted cucumber beetle Striped cucumber beetle

All plant parts are affected

Bacterial wilt disease bacterial ooze

Organic management Difficult to hand-pick; must be controlled early in season. Exclude with floating row cover. Protect plants prior to flowering with organic insecticides (apply to both sides of leaves). Seal up badly infested plants in plastic bag. Plant late; plant multiple crops.

Squash bug

Squash bug eggs and immatures

Squash bug parasitoid

Organic management Remove plant debris to eliminate overwintering sites. Hand-pick adults and eggs; trap with wooden boards. Floating row cover from transplant to flower. Plant late (mid-June) or plant a spring squash trap crop.

Wilted squash- what could be wrong?

Squash vine borer

Very common lethal pest; attacks squashes and pumpkin. Pupae over-winter below soil; moths emerge in spring and inconspicuous eggs are laid singly on stems. Cream colored larva with brown head; 1 inch long when mature. 1-2 generations/year.

Organic management: before signs of injury Set out 3-4 week old transplants after danger of frost to get a jump on this pest. Cover plants with floating row cover until flowering to prevent egg-laying. Spray lower stems with pyrethrum or spinosad. Till soil at season’s end to kill/expose svb cocoons. Butternut and cushaw are resistant; yellow crookneck less susceptible than zucchini.

Organic management: after signs of injury Locate active borers by slitting the vine vertically where frass is kicked out. Kill borer. Mound soil over the wound or wrap with duct tape. Seal up infested vines in plastic bag before larvae pupate (break life cycle.)

Squash beetle Three life stages of the squash beetle. Similar in appearance and feeding habit to Mexican bean beetle.

Downy mildew of cucurbits can be a devastating disease for farmers and gardeners.

Powdery mildew of cucurbits is very common. Select resistant cultivars when possible.

Numerous viruses, transmitted by insect feeding, may infect cucurbits. Leaves may appear distorted, strappy, and multi-colored. Non-human animals also enjoy cucurbits!

Resources Home and Garden Information Center (HGIC) – “hotline”: – “Ask an Expert”- extension.umd.edu/hgic Grow-It-Eat-It website – extension.umd.edu/growit; click “Vegetables” Master Gardener state website – extension.umd.edu/mg

Many thanks to UME Master Gardeners, especially Grow It Eat It bloggers, who provided photos and Powerpoint slides: Erica Smith (head blogger), Nancy Robson, Audra Russell, Kent Phillips, Donna Koczaja, Nick Tardiff, Lena Rotenberg, Butch Willard, Sabine Harvey, Bob Nixon Prepared by Jon Traunfeld, Extension Specialist, and Donna Koczaja and Nicholas Tardiff, UME Master Gardeners. October, 2013