protected crops pt 2 (lecture 5-9)

what are the kinds of capsicums?

blocky sweet peppers, cocktail capsicums, elongated cone-shaped

are capsicums determinate or indeterminate?

indeterminate

capsicums take this amount of time from seed to harvest

20 weeks

capsicums can be harvested for this amount of time

8 months

what are the benefits of coco coir?

• renewable

• retains water well

• natural CEC gives nutrient buffer

• good alternative for long-term crops

what are the layers in coco coir?

fibre (drainage), pith (water retention), chips (structure)

how many plants can be in one coco coir bag?

2 to 3 plants

how many drip irrigation emitters are needed per plant in coco coir?

2

coir hold more water than rockwool, therefore

fewer irrigations, longer cycles

what is the ideal pepper root temp?

20–21°C

what are the disadvantages of coir?

• variation in quality

• must be washed/buffered (remove K/Na

• salt can accumulate in recirculating systems

• disposal requires composting or reuse planning

what is the ideal capsicum planting density?

3–6 plants per m²

how are capsicums trained?

two stems per plant

how many stems per m²?

high light: 8–12 stems per m²

low light: 5–6 stems per m²

what is the optimum temp for capsicums?

21–24°C

what is the minimum threshold temp for capsicums?

8–12°C

what is the cropping difference between rockwool and coir?

rockwool: 1–2 crops

coir: 4–5 crops

when should capsicums be planted for a full season?

mid to late december (6 week old plants)

how long is a capsicum glasshouse empty for?

2–3 weeks for removal, washing down, disinfecting, and preparing for new crop

what are the challenges in irish capsicum production?

low winter temps, cost of fuel, cost of supplementary lighting

do capsicums self-pollinate?

yes

how are capsicums pollinated?

electric pollination, bumblebees

at low temps, fruit is

set without fertilisation; parthenocarpic (seedless) fruit

what is the result of poor pollination in capsicums?

undersized or misshapen fruit

how can bumblebees aid capsicum fruit set?

increase fruit weight, width, volume, seed weight, and ripening speed

what is the main factor affecting fruit set in capsicums?

temperature (optimum at night: 18–27°C)

as the number of fruits per plant increases

average fruit size may decrease

this practice can allow plants to focus resources on fewer, larger fruits

restriction of fruit set

why should bumble bees be used in low numbers in capsicum production?

very active, can damage developing fruit

a capsicum flush is when

all fruit comes at once

how do low temps affect capsicum fruit set?

increases fruit set, though development may be hindered by pollen infertility

how does temp affect capsicum fruit size?

smaller fruits at lower temps, etc

what causes malformed fruit in capsicums?

temp problems during pollination

how are capsicums trained?

plants are pruned to leave two strongest stems; v system

use proper support to prevent breakage

why are lateral shoots removed in capsicums?

maintain vigour in main shoot apex (vertical growth)

when is capsicum growth stopped?

around 4m

why are capsicums pruned?

maintain desired architecture, increase circulation, maximise fruit production, maintain balance between vegetative + generative growth

how often are capsicums pruned?

every 2 weeks

where do pepper flowers develop?

on each node

when are seedlings given nutrient solution, and which nutrients are they given?

once cotyledons expand, solution of equal amounts N and K (ratio determined by crop stage, light levels, climate)

silvering and blossom end rot in capsicums is a result of

calcium deficiency

botrytis cinerea and phythophthora capsici both cause

seedling damping off, root rot, stem cankers, lesions

what are common pests of capsicums?

aphids, red spider mites, western flower thrips, whitefly

what are common diseases in capsicums?

damping off, crown and root rots, fusarium stem and root rot, grey mould

what are viral diseases in capsicums?

pepper mild mottle virus, tobacco mosaic virus, tomato spotted wilt virus

what are common physiological disorders in capsicums?

• flower, bud, and fruitlet abscission

• blossom end rot, fruit cracking, silvering, sunscald

what are causes of physiological disorders in capsicums?

• high temps

• low temps

• low light

• plant stress

• rapidly growing fruit

• pests and diseases

what is a typical capsicum yield?

22–32 kg per m²

how long between fruit set and harvest for capsicums?

7–9 weeks

what does perlite offer?

good aeration, low disease carryover

what is the planting density for cucumbers?

high wire: 2.5–3 plants per m²

umbrella/shorter cultivars: 3.5–4 per m2

in perlite systems, why do nutrients come exclusively from fertigation?

low cation exchange

how often should you irrigate perlite substrates?

often; multiple short irrigations over the day

what is the ideal root temp for cucumbers?

18–22°C

what is the ideal temp for cucumbers?

24–30°C

how much light should cucumbers get in the propagation stage?

12–16 hours

modern cucumber varieties are gynoecious and parthenocarpic, so

no pollination is not required, can cause deformities

cucumber growth is

indeterminate

how are cucumbers trained?

pruned to balance vegetative and reproductive growth, fruit removed to stimulate shoot growth and discourage malformed fruit

what is the umbrella training system (cucumbers)?

single stem until wire, then main growing point snipped and stem split into two laterals

what is the vertical cordon system (cucumbers)?

long single stems, can be vertical or inclined

what are vertical cordon systems good for?

long-season crop

how should cucumbers be stored?

10–15°C, 90% RH, wrap to retain moisture

what is the yield of cucumbers?

50–65 kg per m² person year

how heavy is an average cucumber?

375–550g

what are common pests of cucumbers?

two-spotted mite (!!), whitefly, thrips, caterpillars

what are diseases of cucumbers?

cucumber mosaic virus, powdery mildew

what are common disorders in cucumbers?

crooking (pressure, insect feeding, nutrition), abscission (sudden temp change)

in what areas is soil better than hydroponic systems?

setup cost, microbial activity, and organic certification

why does salinity and compaction tend to develop in covered soils?

lack of natural rainfall and leaching leads to salt accumulation

what kind of soul does celery prefer?

fertile, well drained peat or mineral soil

why does celery need more frequent, lighter irrigation?

shallow root system

what is the ideal temp for celery?

18–24°C

how much water and feed does celery need?

a lot LMAO frequent watering, lots of N, P,K, Ca

what is the ideal pH range for celery?

6–6.8

why should celery irrigation be reduced closer to harvest?

to prevent rot

how can micronutrient deficiencies in celery be treated?

foliar sprays

why are drip lines good for shallow-root crops?

frequent light irrigation; conserves water and prevents splash

when is the majority of M applied to celery?

at planting time

what are the signs of N deficiency in celery?

stunted growth, pale green foliage, yellowing of older leaves and early senescence

what is a sign of Ca deficiency in celery?

blackheart

what is a sign of boron deficiency in celery?

stem cracking

how is fertility managed in celery cropping systems?

base fertiliser before planting, supplement with drip fertigation, balance N:P:K for crop stage to avoid salt buildup

what are some problems with covered soil?

waterlogging and poor aeration, buildup of salts, soil fatigue, pest/disease carryover between crops

what are some common pests in covered soil systems?

aphids, thrips, slugs, leaf miners, celery fly

what are some major soil-borne diseases?

fusarium, sclerotinia, pythian/rhizoctonia, cercospore/septoria

what celery pathogen causes leaf blight?

cercospora or septoria

what celery pathogen causes pink rot?

scleroctinia

what celery pathogen causes yellows?

fusarium

what celery disease is spread by leaf hoppers?

aster yellows

what are sterilisation options in covered soil systems?

flaming, steaming, chemical fumigation