Rich Marini Department of Horticulture Penn State University Vegetable Garden Rich Marini Department of Horticulture Penn State University

Unit 1: Garden Planning (Let’s Plan) Preparing for a Vegetable Garden Making the most of the Garden Space

Preparing for a Garden Develop plans in February Select a site – avoid shade, poor soil, wet and low areas, and walnut trees List the vegetable species & varieties – consider season Decide how much to grow – how will produce be used Make a planting map

Planting Map (24’ x 50’) gr. beans (4/15) gr. beans (5/8) North pumpkins melons 6’ spinach (3/20) lettuce(3/20) radishes (3/20) Onions (4/1) gr. beans (4/15) gr. beans (5/8) carrots (4/15) peppers (5/15) 2’ 2’ 3’ 4’ corn (4/15) corn (5/1) corn (5/15) 3’ corn (4/15) corn (5/1) corn (5/15) 3’ North

Planning suggestions Put vine crops on the edge Plant 3 rows of corn for pollination Put tall plants on north side Plant small amounts several times to extent the harvest season 1,000 sq. ft. takes about 1 hr per week of care

Other considerations Rather than rows, can plant broadcast (no rows), but rows are easier to care for Consider equipment size for row spacing Double crop to use space efficiently – Harvest radishes, peas, lettuce early then plant late-season crops in same space (peppers, beans, summer squash)

Develop a Garden Calendar January – look at seed catalogues February – Order seeds March – Plant peppers indoors, test soil April – plant early season crops May – Sept. – grow garden Oct. – clean up garden

Unit 2. Planting a Garden Understanding soils – soils provide support, water, and mineral nutrients Soil is composed of sand, silt, clay and organic matter Soil has living organisms – worms, insects, fungi, bacteria: some are pests, some are beneficial If too much clay, add organic matter

Soil Chemistry Soil pH should be slightly acid (6.0 – 6.8) Too low: macronutrients are deficient Too high: micronutrients become toxic Macros: N, P, K, Ca, Mg Micros: Fe, Cu, Mn, B, S, Zn Most soils have enough of everything except N,P,K – complete fertilizer

Soil Physical Characteristics Sand – large particles, good for water drainage Clay – very small particles, holds lots of nutrients, hard to dig, poor water movement Silt – intermediate size, water moves slowly Organic matter – holds water and provides nutrients and supports micro-organisms

Buying plants & seeds Buy current season’s seeds May have to order unusual varieties Look for disease resistant varieties Buy good-quality plants – look for new shipments – avoid yellow or wilted plants

Artificial Soil Mixes Fewer disease problems than real soil Usually contain fertilizer Some brands better than others I like “Mirical-Gro”, but others may be good Usually contain peat, vermiculite & perlite and fertilizer

Starting Plants Indoors Need warm sunny place Don’t start too early, plants will be pot-bound and “leggy” Transplant to pots when about 1.5” tall Put outdoors as soon as possible

Planting in the garden Cultivate the soil and incorporate fertilizer and lime Use string to make straight rows Small seeds are barely covered, plant large seeds 2 times their diameter in depth Thin plants to appropriate distance – follow directions on the packet

Transplanting “Harden” plants by growing outdoors for about a week Plant at about the same depth as in pot Remove peat-pot bottom and side Water Avoid hot sunny, windy days

3. While You wait – Plant Science Seeds – a seed is an embryo, a tiny plant with root parts, a stem, and about 6 leaves. A seed coat protects the embryo Have a food supply until there is adequate foliage to produce enough carbohydrate Endosperm and cotyledons (specialized leaves) – starch (corn & wheat) or oil (beans). Coconut “milk” is liquid endosperm.

Two kinds of plants Monocots: one cotyledons – grasses Dicots: two cotyledons – beans, apple, maple, tomato

Seeds and Seedling

Dicot and Monocot Seedling

Dicot Seedling True leaf Cotyledons

Conditions for seed germination Seeds are living organs Need Oxygen for respiration to generate energy from food supplies Need Water (imbibition) for cell expansion and for photosynthesis and biochemical reactions Proper temperature – 45 degrees for lettuce, 70 degrees for pepper

Water and air enter through the seed coat and carbon dioxide exit through the coat. Some seeds (lettuce) require light (red light) to stimulation of hormones If planted too deep, leaves don’t reach light before food reserves are used up. Some seeds have hard thick seed coats and must be scarified (stratch the seed coat) to allow water in.

Germination requirements Seed coats also contain “inhibitors” and some need to soak to leach out inhibitors. Some seeds require a chilling period (vernalization) to break dormancy (apple seeds need 1,000 hrs below 45 degrees F) Hormones (gibberellins) may overcome dormancy

Common reasons for lack of germination Improper soil temperature Soil too dry Seeds planted too deep Seeds washed away Damping-off disease (fungus)

Basic Plant Needs Light Water Mineral nutrients Air (oxygen & carbon dioxide) Proper temperature

Photosynthesis A biochemical reaction in the cells of green tissues. Chlorophyll is the green pigment in organelles called chloroplasts

Photosynthesis Requires the green pigment (chlorophyll) in the chloroplast within the cell. The light cycle requires light for energy . Water is split into hydrogen and oxygen. The dark cycle occurs in the dark or light where hydrogen combines with carbon dioxide to form glucose. Oxygen is passed through the stomates. Glucose or sucrose transported through the phloem throughout the plant.

Light for photosynthesis Chlorophyll absorbs light energy to convert carbon dioxide and water into sugars. Oxygen is also produced. Gases (oxygen, carbon dioxide & water) pass in and out of leaves through small holes called stomates.

Respiration Within specialized organelles (mitochondria) in the cells, sugars are converted to energy which is used for plant growth. Oxygen is used and carbon dioxide is produced.

Plant parts - Roots May store sugars (sugar beet, carrot) or starch (woody roots, sweet potato) 2 types of roots Primary tap root: long strong roots (some trees, carrots, dandelion) Fibrous roots: short thin roots arising from larger roots (beans & tomato) Root hairs are extensions of cells on the root surface (epidermal cells). These very small structures absorb most of the water and nutrients.

Root Motion Roots normally grow down. They are sensitive to gravity (geotropism).

Stems Connect leaves and roots, and supports leaves for light exposure. Similar to a pipe. Water and mineral nutrients move up in the xylem. Sugar solution moves down in the phloem. Some stems store food – starch in potato, starch in tree trunks in winter, sugar in sugar cane.

Simplified stem cross-section Epidermis - Xylem Phloem

Longitudinal section of a woody stem

Stem function Epidermis – one layer of waxy cells Phloem – live cells Xylem – long dead cells lined up end-to-end to produce a “pipe” Vascular Cambium – a cylinder several cells thick between the phloem and xylem. Responsible for diameter increase: produces xylem cells to the inside and phloem cells to the outside

Geotropism A plants grow in response to gravity Positive geotropism – roots bend toward gravity Negative geotropism – stems bend away from gravity Curvature is caused by unequal growth on the 2 sides of the axis

Auxin – a plant hormone Produced in young leaves, shoot tips (meristems) and seeds. Auxin moves with gravity, causes bud dormancy and causes cell elongation

Growing tip

Tomato Gravitropism

Phototropism Auxin Auxin

Motion of stems Phototropism - Stems bend toward light. Auxin is destroyed by light, so cells on the dark side elongate and cause bending toward light. Auxin produced in the shoot tip moves down the stem and accumulates on the lower side of the stem, so stems bend up. Root growth in inhibited by auxin. Auxin accumulates on lower side, so roots grow down

Apical dominance Buds actually are short stems with about 6 leaves. Auxin moves from the apex down and inhibits buds. Removing the apex (pinching) allows the buds below the apex to grow. This causes branching.

Carbohydrate transport Sugars can be used for energy or converted to structural molecules such as cellulose (cell walls), fats and proteins. Sugars move from areas of high concentration (leaves) to areas of low concentration in the phloem.

Flowers – modified stems At some point buds switch from vegetative to reproductive – environmental cues. Flowers are reproductive structures and attractive insects. Pollen produced on anthers is transferred to the stigma, then germinates and grows down the style to the ovary where the sperm fertilizes egg to produce a seed.

Types of flowers Perfect flowers have both pistils and stamens (peas, bean, tomato, apple) Imperfect flowers are either male or female (cucumbers, melons, squash). Some species have male and female plants (ginko trees).

Flower Parts

Fruits As ovules develop into seeds within the ovary, the ovary swells and becomes fleshy or hardens to protect the seeds. Fruit helps seeds disseminate. Fleshy fruit (squash, tomato, grape) have fleshy ovaries surrounding the seeds. Dry fruits have ovaries with thin, dry walls. Corn, wheat, oats and each fruit is a single seed. Beans are dry fruits with a nonfleshy pod containing several seeds.

Seeds

Varieties of bean seeds

Tomato Fruit with Seeds

Bean fruit and seed

How do we make new plants? Plant Propagation Sexual – from seeds: Allows a species to survive by perpetuating genetic variation Asexual or vegetative – produce new plants from parts of a plant to maintain genetic identify. Produces clones.

Vegetative propagation Stems – potato, bulbs Cuttings – roots can be produced by leaves or stems Grafting – join a scion variety onto a rootstock scion Match up cambiums rootstock

Plant Life Cycle Seeds geminate Plant grows, matures, and flowers Produces fruit and seeds Plant dies Annuals live 1 year (lettuce, beans) Biennials flower second year, then die (carrot, onion) Perennials live many years (asparagus)

Plant improvement Natural selection: In the wild, individuals within a species differ. Those with characteristics enabling them to survive to reproductive age pass on their genes to the next generation. Man has domesticated plants and animals by selecting individuals with the characteristics we want.

Plant breeding Plant breeding: During the last century we have controlled pollination to develop hybrids or new varieties with outstanding characteristics Examples include high yield, large fruit, different flower colors, disease resistance. There is some concern that we have reduced genetic variation too much, new strains of disease may devastate a crop

Biotechnology A set of techniques used to study and modify genes. Examples FLAVR SAVR tomato – doesn’t produce the ripening hormone ethylene, so it can be stored a long time before exposing it to ethylene to cause ripening Some corn varieties contain the BT gene for resistance to worms

Genetic Engineering Transferring specific genetic material from one organism to another. Examples: Put the gene from a firefly into a tobacco plant and the plant glows in the dark. Put an antibacterial gene from a moth into an apple tree to make it resistant to bacteria.

Preserving genetic diversity We want to save genetic variation to use in breeding programs. USDA maintains repositories for major crops; both seeds and plants. USDA funds plant collecting expeditions to “centers of origin” for major crop species

Interdependence (Ecology) All organisms are connected. Some plants rely on animals to transfer pollen and disseminate seed. Some plants rely on fungi to improve root function. Animals rely on plants to convert solar energy (sun light) to chemical energy (sugars)

Human impact on ecology Acid rain is killing the eastern forest Ozone, from car emissions, injures some plant species Pesticides and other chemicals may injure non-target organisms Global warming may alter the distribution of organisms and agricultural productivity

Hydroponics We can provide support and nutrients for plants without soil Commercial greenhouse tomatoes are often grown hydroponically in shallow trays of flowing water containing fertilizer. Most greenhouse crops are grown in soiless mixes of sand, perlite, vermiculite, and peat

Unit 4. Garden Care Soil fertility – At least 2 months before planting contact local Extension office for soil testing kit. Fertilize & lime according to recommendations. Apply lime to raise soil pH and reduce acidity (about 6.2 to 6.8) Apply complete fertilizer to provide nitrogen, phosphorous, potassium

Organic Matter Organic matter provides nutrients and improves soil structure and water holding capacity. Also encourages many soil organisms – worms, insects, fungi, bacteria Sources – compost, manure, bone meal

Garden Equipment Hoe, rake, trowel, watering can, hose, short stakes and string to mark rows, long stakes for supporting plants, hot caps, sprayer, tiller Pesticides – read the label Store locked up Leave in original container Avoid freezing or hot environments

Frost Site selection – avoid low areas because cold air is heavier than warm air and flows down hill just like water. Tender plants, such as tomato, peppers, squash are killed at about 30° F Cool season crops, such as cabbage, broccoli tolerate a light frost (27° F), and carrots, beets, lettuce tolerate 22° F

Frost protection Cover plants with hot caps, newspaper tents, or mulch with straw Overhead irrigation Late season frost – harvest as much as possible before the frost

How does irrigation work? As water freezes it releases heat. Ice provides little insulation, so irrigation must continue to freeze until the temperature increases above 32° F and all ice has melted Don’t irrigate when due point is low and there is wind because evaporation requires heat and heat will be removed from plants

How do hot caps work? Greenhouse effect During the day short-wave solar radiation is absorbed by soil and exits the soil at night as long-wave radiation. Hot caps provide a barrier to long-wave lengths which are redirected toward the soil. Frosts are rare on cloudy nights because clouds allow short waves, but not long waves, to pass through.

Managing weeds Weeds are plants growing where they are not wanted Weeds compete for light, water & nutrients Best to eliminate weeds when small Mechanical control – pull by hand, hoe, cultivation. This must be done every 10 to 14 days depending on rain. Weed seeds can remain dormant in soil for many years.

Mulch to control weeds Can use straw, shredded paper, thin layer of grass clippings or plastic Also helps conserve water, reduces soil erosion and keeps plants clean Apply mulch early, before weeds come up

Herbicides Chemicals that control weeds May control grasses, broadleafs or both Pre-emergent herbicides prevent seeds germination Post-emergent herbicides kill plants on contact Not recommended for home garden

Plant diseases Infection requires Susceptible host plant Presence of the pathogen Proper environment for disease development Powdery mildew requires hot dry conditions, and early blight on tomato requires wet conditions Viruses spread by insect vectors

Managing plant diseases Caused by fungi, bacteria, nematodes or virus Select resistant varieties when possible Encourage quick drying – avoid shade, control weeds, leave space between plants

Controlling diseases Cultural control – good drying conditions, resistant varieties, remove diseased plants Fungicides and antibiotics – these are preventative and must be applied before infection occurs. Apply every 10 to 14 days to protect new growth and replace residue washed off by rain.

Diseases of squash Powdery mildew Septoria leaf spot Virus

Non-pathogenic problems Sunscald heat injury to fruit Cold growing conditions can cause plants to turn purple due to poor phosphorous uptake Too much fertilizer can burn roots and cause wilting Too much pesticide can damage leaves

Insect pests Many types of insects can feed on plants. Grubs (immature beetles) feed on roots Worms (immature moths) feed on leaves, fruit, or tunnel into stems (borers) Maggots (immature flies) feed on fruit & roots Beetles, aphids, and true bugs feed on leaves

Japanese beetle life cycle

Controlling insects No resistant varieties, except for genetically modified varieties of corn and soybeans (BT genes) Use insecticides to kill insects Monitor plants every week Don’t apply until you see pests Use “soft’ materials that protect nontarget organisms

Aphids

Corn Ear Worm Life Cycle Adult Larvae Pupae

Natural vs. man-made pesticides All are poisonous and should be treated with care Natural materials usually are broad-spectrum and kill nontarget species, and they must be applied more frequently because they are less residual Insecticidal soaps are effective Many insects are beneficial and we want to protect them

5. Harvest & storage Important to harvest vegetables at proper stage. If many leafy vegetables are left too long, they will produce flowers Peppers are ready when they are full size, can wait and harvest them red Tomato can be harvested when just beginning to turn red Cantaloupes are harvested when stem slips off the melon

Other vegetables Zucchini, summer squash, and cucumbers are harvested when fairly small (before seeds enlarge) and need to be harvested every day or two. Potatoes are harvested when leaves start to die in late summer Onions are mature when leaves fall over

Storage Harvested plant parts are living tissues and continue to respire. We want to slow down respiration so the cells remain alive High humidity for leafy vegetables – put in perforated poly bags Temperature is most important Most vegetables store well in the refrigerator (about 40ºF) Peppers store at about 50ºF

Unit 6: Careers Without a college degree Farm, greenhouse, florist worker Assistant manager, retail market Landscape worker 2-yr Associate degree in plant science Assistant superintendent for golf course Farm & retail store manger Arborist, flower shop manager

4-yr degree programs Crop protection – entomology, plant pathology, weed science Environmental sciences Ag economics - farm management, rural development Horticulture, landscape architecture & landscape contracting Plant genetics & plant breeding

Careers with B.S. degree Teach agriculture and science Ag. Chemical sales, exterminator Government agencies (USDA, DEP, EPA) Manager of farms, retail centers, nurseries, flower shop Landscape architect, Landscape contractor, golf course superintendent Plant breeder

Careers with M.S. degree Research technician with chemical company, university, USDA, private lab Plant breeder Produce wholesale & marketing International agriculture Government agencies Ag sales and marketing Extension agent Teach at community college Public gardens & arboreta

Careers with Ph.D. Academia (teach, research, extension) Ag. Chemical company R&D International agriculture Plant breeder Industrial research – Ag. Chemicals, plastics, greenhouses Marketing Government agencies (USDA, EPA, DOE, DEP, PDA)

Other considerations Rather than rows, can plant broadcast (no rows), but rows are easier to care for Consider equipment size for row spacing Double crop to use space efficiently – Harvest radishes, peas, lettuce early then plant late-season crops in same space (peppers, beans, summer squash)