Care of plants in interior situation

Question 1

Describe environmental factors to take into account when displaying plants inside domestic buildings

Answer 1

• Temperature: 18-24 C sufficient for most interior plants. Fluctuating temp damages plant growth. Low temperatures will result in poor, weak, slow growth and lack of flower buds. High temperatures with dry out growing media and possible leaf damage.
• Humidity: most houseplants prefer RH 60%, most homes <40%.
  
  • Central heating produces dry heat / low humidity.
  • Set plants on trays of gravel/pebbles that is kept moist to increase humidity immediately around plant
  • Grouping plants together increases RH
• Light
  
  • day length and quality of light
  • number and size of windows, orientation, type of window coverings, obstruction outside of windows
• Irrigation/water: frequency of watering dependent on:
  
  • type and age of plant, size and type of container, growing media, time of year e.g. if plant dormant, environmental conditions e.g. light and temperature
  • Under watering → wilting, over-watering → root rot
  • Overhead watering requires more regular checking and application. Sub-irrigation provides a more even water supply,
    without fluctuations.
• Air movement: space just inside window may be cold and draughty, draughts from external doors.
• Pollution and dust: photosynthesis reduced by dust, cigarette smoke and cleaning products, which can block the leaf stomata and coat the upper surface, affecting plant growth. Clean foliage regularly by wiping with a damp cloth to remove any pollutants and dust build-up.
• Health and safety: spiky and thorny plants can be dangerous, especially to children. Poisonous plants can cause allergic reactions. Make sure containers containing large plants are stable, so they can’t fall over and cause injury. Also site large containers in places that don’t form a tripping hazard.
• Public pedestrian traffic

Question 2

Describe choice of suitable growing containers for house plants

Answer 2

Question 3

Describe choice of growing media for house plants

Answer 3

• Adequate drainage and aeration- ensures growing media remains ’sweet’ by maintaining good air to water ratio, avoiding anaerobic conditions within root environment, well aerated for aerobic respiration to take place.
• Good water retention, ability to retain moisture and make available to the plant—so ensures plants remain turgid and doesn’t wilt. Without water nutrients unable to be taken up via the root system—essential for plant growth.
• Good nutrient availability - retains nutrients and given to plant over extended periods of time, to avoid nutrient deficiencies and enable healthy plant growth.
• Lightweight growing media - enables plants to be easily moved.
• Hygiene

Ingredients used in house plant growing media: Peat, sharp sand or horticultural grit, loam, bark, controlled release fertilisers and coir

Question 4

Management of Adiantum raddianum (Delta maidenhair fern)

Answer 4

• Feeding: Feed once a month in spring and summer with a weak balanced liquid feed.
• Watering: Grow in moisture retentive well-drained soil, make sure the soil doesn’t dry out, keeping it moist but not waterlogged. Ideally use rain water.
• Environmental control:
  
  • Does best in a humid environment e.g. bathroom. Mist at least every couple of days or place on a dish of moist pebbles filled with water. RH 60-80%.
  • In bright indirect light in the summer and full light in the winter months
  • Kept away from draughts
• Re-potting: Re-potted once root bound. Use high organic matter growing media which is moisture retentive, remove from existing pot and place in centre of new one half full of growing media. Correct depth of no deeper than top of root ball, no fronds buried and firmed.
• P&D identification and control: Leaves turn brown when something is wrong with its growing conditions.
  
  • Red spider mite, scale insect - isolate or dispose of infected plants.
  • Scale insects - flat, tiny, sap sucker, leave sticky coating on frond. Found on stems and frond backs along central vein. Affected areas weakened and yellow. Insects excrete stick honeydew on fronds.
  • Botrytis/grey mould - control by optimal environmental conditions, good aeration, not waterlogged.
• Propagation:
• Establishment:

Question 5

Management of Ficus benjamina (weeping fig) (foliage plant)

Answer 5

Weeping figs are fussy about their growing conditions and will drop their leaves if they are not happy.

• Propagation: propagated from stem tip cuttings. Material that is healthy, true to type, and P&D free is removed from stock plant just above a node 7.5-10cm in length. Cutting prepared by trimming just below a node at base to 5-7.5cm and removing lower third of leaves. Cuttings placed in closed case with basal temp 21-24 C and high relative humidity to reduce moisture loss.
• Potting: into a 9cm pot once cuttings sufficiently rooted using a potting compost which is sufficiently water retentive but well drained and contains a low level of nutrients e.g. JI no. 1. Rooted cutting carefully removed from tray and any damaged leaves etc. removed before placing in centre of pot at correct level and settling compost around root system which is completely covered. Do not bury basal leaves.
• Establishment: They need bright but indirect light and a steady temperature of at least 16°C to thrive.
• Feeding: feed with slow release fertiliser at start of growing season or feed once per month with standard houseplant fertiliser.
• Watering: regular watering, don’t allow to dry out, kept near container capacity. Water regularly when the top of soil is dry to the touch. Do keep the lower soil moist but do not allow the pot to sit in water as it will drop leaves and lead to root rot.
• Environmental control: keep away from draughts. Likes humid environment. Does not like to be moved around the home, will drop leaves.
• Re-potting: do not appreciate being repotted frequently – it can cause them to lose their leaves. Repot young plants in spring if they need it, into a slightly larger pot. Knock out pot, tease roots (prevent root curl), pot into 14cm pot using John Innes no.2. Centre of pot, same depth as original root ball..
• P&D identification and control: Red spider mite causes fine mottling of leaf , fine silk strands may also be visible on underside of leaf- cultural control - increase humidity in a glasshouse, biological predatory mite or chemical: fatty acids. Also woolly aphid (wipe down leaves with slightly soapy water) and mealy bug.
  *

Question 6

Management of Euphorbia pulcherrima (Poinsettia) (seasonal flowering plant)

Answer 6

• Environmental control: bright, indirect light, in a draught-free spot with a temperature of around 13-15°C
• Feeding: Base dressing of balanced fertiliser into growing media or applied as top dressing during growing season. Nitrogen = healthy leaf growth, Potassium = encourage flowering and bract formation. During time subject to short day lengths to develop blooms apply extra fertiliser every other week.
• Watering: Regular watering by watering can with fine rose attachment or drip or capillary irrigation systems. Make sure plants not stressed or wilt.
• Re-potting: Plants re-potted into larger pots during spring months to allow root development to take place. John Innes no.2 growing media. Handle plants carefully to avoid damage. Pot at correct depth in the centre of the pot and firm well.
• P&D identification and control: whitefly, control = biological parasitic wasp Encarsia Formosa or fatty acid chemicals.
• Establishment: flowers when day length less than 10 hours. To flower at Christmas from 1 October place plant in complete darkness for 14 hours per day

Question 7

Management of Kalanchoe blossfeldiana (Flaming Katy) (seasonal flowering plant)

Answer 7

• Feeding: Via controlled release fertiliser in the growing media or as a liquid feed through the irrigation system. Feed with liquid fertiliser every 2-3 weeks during growing season
• Watering: when dry (plant pot will be light). Watered overhead or by capillary watering moderately during growing season, and then just kept moist (not damp) during the winter. Drought tolerant plants.
• Environmental control: Bright light to full sun. Flowers when day length less than 11-12.5 hours
• Deadheading: remove dead flowers as they appear.
• Propagation: propagated by seed. Sterile trays overfilled with JI seed sowing compost. Tray tapped to settle compost, levelled and firmed. Fine seed is mixed with 50:50 with dry silver sand to aid distribution and mixture is evenly distributed over surface of tray. Seeds germinated at 18-24C. Pricked out once large enough to handle. Can also be propagated with cuttings.
• Potting: once seedlings have suitable root system potted into 9cm pots in JI no.1 potting mix. Half fill pot with compost and hold plant in centre at correct depth to ensure will be at same depth as in tray. Fill pot gently around plant, leaving space for water, firm in. Water to settle compost.
• Re-potting: planted potted into 9cm pots when rooted using e.g. JI no.1 . All pots and media should be sterile and plants should be graded, remove damaged material. Pot in centre of pot to level just above top of roots and firm. Re-pot into 1 litre pot with John Innes no.2 or multi-purpose compost when roots have filled 9cm pot. Needs well-drained potting mixture.
• P&D identification and control: Aphids, cultural control: good plant husbandry and use of soft soap. Botrytis - control - avoid high relative humidity, provide good ventilation, removal of dead/damaged/diseased plant material. Mealy bugs most common.

Question 8

Management of Saintpaulia ionantha (African violet)

(seasonal flowering plant)

Answer 8

• Feeding: Can include base dressing in potting compost. Feed with standard liquid fertiliser every 2 weeks spring to autumn. Foliar feed not suitable as hairy foliage and water droplets will cause scorch.
• Watering: water from below, or drip or capillary irrigation to not damage/scorch the hairy/hirsute foliage. Provides higher relative humidity which is beneficial to the plant—so importance of reasonably high moisture content in root environment. Rain water or soft water is preferable - avoid lime build-up in the pot.
• Deadheading: removed dead flowers as they appear.
• Propagation: leaf petiole cutting in spring. Choose leaves that are almost full size and remove with the stalk attached. Fill pots with free-draining, such as seed and cuttings compost. Insert the leaf stalk into the compost so the base of the leaf just touches the surface. Water, and allow to drain. Place pots in a propagator or cover with a clear plastic bag, and provide bright but not direct light. Keep at 18°C. New plants should form at the base of the leaf in 4-5 weeks. At this point, remove the lid or plastic bag and allow them to grow on. Pot up individually once they have several leaves.
• Potting up: young plantlets must be potted up into 9cm pots separately to avoid multi-crown plant using an appropriate compost e.g. JI no.1. Do not bury the central growing point, centralise plant in pot, handle plant with care to avoid damage. Water plant to settle compost around root system but avoid wetting foliage.
• Re-potting: Re-potting, when pot bound, is the transfer of the established plant into one size larger pot using JI no.2 growing media, (don’t
  bury too deep, note plants have a fibrous shallow root system) to maintain optimum growth. Knock plant out of pot, tease roots, Dead or damaged leaves or leaf petioles are carefully removed and multi-headed plants can be split before potting. Plants must not be potted too deep, centre of pot, gently firmed in, at same height as previous pot. Water in, but not wetting foliage.
• P&D identification and control: red spider mite, aphids, whitefly, scale insect, vine weevil—eat plant roots, cause stunted growth. Biological control = parasitic eelworm. Nematode watered into soil August -September after adult stopped laying eggs. Pots must be kept moist for two weeks after application to ensure all larvae are killed. Botrytis, powdery mildew