Cultural Notes: July-Aug-Sept

Cattleya, species and hybrids 

Including those plants formerly labelled Laelia, Slc, Blc, etc, with the exception of C. dowiana which is happier with a minimum of 10-12deg.

Water, July-Aug: Water sparingly and allow the mix to become rather dryish before watering again. When in doubt don’t water. Sept: Temperatures will be rising now so increase water but still let the mix become dryish between waterings.

Fertiliser, July-Aug: Quarter- to half-strength every second or third watering. Sept: Half-strength every second watering.

Light, July-Aug: 30% shade or less. Sept: 30% shade.

Temperature, July-Aug: Ambient day; about 5C at night. Sept: Ambient day; 5-10C at night.

Flowering: Depending on the variety these plants can bloom at various times of the year but the flowers in all cases develop in the same way – the spike/buds form within a ‘sheath’ on top of the most  recent growth. It can be a good idea to split this sheath at the top to allow the flower stem to emerge easily.

Other: The ‘Mexican’ Laelia types (anceps, autumnalis, gouldiana) develop flower stems with the new growth and typically bloom from mid-winter to early spring. L. purpurata types produce their flowers from within a sheath and bloom some time after the new growth has reached maturity usually in the summer months.

Cymbidium, species & hybrids

Water, July: Thorough water on the morning of a day that you would expect washing to dry. Small pots require water more often. Every 10-14 days. Aug: Thorough water on the morning of a day that you would expect washing to dry. Small pots require water more often. Every 7-10 days. Sept: Thorough water on the morning of a day that you would expect washing to dry. Small pots require water more often. Every 7 or so days.

Fertiliser, July-Aug-Sept: Half-strength balanced fertiliser every second watering.

Light, July-Aug-Sept: Good light, although whites and especially greens may be better with more shade as this will give cleaner-coloured flowers.

Temperature, July-Aug-Sept: As warm as practical through the day but ventilate at 20C. At night avoid frost and chill factor. Close the house at, say, 3pm to improve minimum night temperature.

Flowering: Keep flower spikes staked and trained to give a pleasing natural arrangement – don’t leave it until the flowers have opened and then stake/train as the result does not look natural and pleasing to the eye. Despite florists, Cymbidium flowers are not naturally presented upside-down, that is lip to the top. However please don’t try to stake and train strongly arching or pendulous stems to an upright position, let them arch or fall gracefully and naturally. Train upright spikes to below bottom flower when temperatures are warm. Don’t shift a plant’s orientation when in spike as this will confuse the flower to come.

Other: Watch for snails, slugs and mice and keep baits out for them – they can eat in one night what you have been waiting to see for the past year!

Dendrobium Australian types (eg kingianum, speciosum)

Water, July-Aug: Water well, really soak the pot, and allow to dry before watering again. Do this on a dull day as usually a dull day is not followed by a frost. As a guide every 10-14 days. Sept: Water well, really soak the pot, and allow to dry before watering again. As temperatures as now rising you will need to increase water frequency.

Fertiliser, July-Aug: Half-strength balanced fertiliser every or every second watering. Sept: Half-strength balanced fertiliser every third or fourth watering.

Light, July-Aug: No shade. Sept: 30% shade.

Temperature, July-Aug: Ambient day; at night ambient or down to 1C. Sept: Ambient day and night.

Flowering, July: Flower spikes from the upper nodes of new and older canes. Aug: Flower spikes much longer. If stems from lower down are being stopped by a leaf in having arching growth then
remove this leaf. Sept: In flower or in bud.

Dendrobium cool-intermediate types (eg densiflorum, thrysiflorum)

Water, July-Aug-Sept: Allow to become somewhat dry between waterings. Increase the water frequency when new growths (and therefore roots) are showing, this could be as early as late August in warmer areas.

Fertiliser, July-Aug-Sept: As the plants are not actively growing little is needed but increase to half-strength when new growth and roots are evident.

Light, July-Aug-Sept: Good bright light (30% shade) over this period gives a stronger more hardy plant and should increase flower production.

Temperature, July-Aug-Sept: Unless you are in a very cold area, ambient daytime temperatures should be fine – 15C and above; down to 3-5C at night is okay.

Flowering: Depending on the variety flower spikes may become evident from the upper nodes of newest and older canes. With this group older canes/stems can continue to produce flowers for several years.

Dendrobium cool-intermediate types not needing a dry winter rest (eg latouria, cuthberstonii)

Water, July-Aug: Keep the plants moist but not wet, don’t let them become dry at the roots. These types typically originate from places where water is available at the roots all year and are in many cases growing all year. However, too wet and cold is dangerous. Sept: Now the days and nights are warming up you can increase the water especially on plants with developing growths and roots.

Fertiliser, July-Aug-Sept: Although these types can be growing all year, at this time around quarter- to half-strength balanced NPK every second or third watering should be fine. Increase to
usual rate when the nights have become warmer and growth is more active.

Light, July-Aug-Sept: Good light, not too shady (30-50% shade). On a sunny day your hand should cast a fuzzy-edged, but definite, shadow.

Temperature, July-Aug-Sept: Ambient daytime; ambient at night but not below 4 -5C. Den cuthbertsonii is okay down to 0C in an enclosed situation.

Dendrobium Dockrillia types (eg linguiformis, teretifolium)

Water, July: Water sparingly – say every week to 10 days. Aug-Sept: In warmer areas you may need to increase water frequency.

Fertiliser, July-Aug-Sept: Half-strength balanced fertiliser every second watering.

Light, July-Aug-Sept: Bright light with little or no shading. Bright light short of burning the plant enhances flowering. (A note regarding light and the development of purplish-red colour on the
leaves under high light, this is okay and normal. More or less an indication that the light is good.)

Temperature, April-May-June: Ambient day; 2-3C as a minimum at night.

Dendrobium soft cane & nobile types

Water, July: Just a little, keep rather dry. Aug: A little more water as temperatures rise and flower buds develop. Sept: Increase water frequency with the development of new growth and roots.

Fertiliser, July: None needed. Aug-Sept: As temperatures rise and new growth/roots are developing begin feeding again with half-strength balanced NPK.

Light, July-Aug: 30% shade or less. Sept: 30% shade.

Temperature, July-Aug: Ambient day; about 5C at night. Sept: Ambient day, 5-10C at night.

Flowering, July: Flower stems will emerge from opposite each leaf on the newest or 2-year-old canes/stems and should be showing now. Aug: Flower buds will be developing and if some of those leaves are in the way then carefully remove them,  it won’t bother the plant. Sept: Enjoy those blooms! And the fragrance!

Masdevallia

Water, July-Aug-Sept: Over the colder months I have found that allowing the plants to become rather more drier between waterings has produced more profuse flowering of the spring/summer blooming types, eg, Masd. coccinea, veitchiana, rolfeana and many hybrids.

Fertiliser, July-Aug-Sept: Half-strength balanced fertiliser every second or third watering.

Light, July-Aug-Sept: 30-50% shade. Try to give the plants as much light as the plants were getting over the spring/summer period. This again will improve flowering.

Temperature, July-Aug-Sept:  Ambient during the day; 2-5C at night.

Miltonia species & hybrids

Water, July-Aug: Water sparingly, but ensure the mix stays damp but not wet. If in doubt, don’t water. Sept: Temperatures will be rising now so increase water but still let the mix become dryish between waterings.

Fertiliser, July-Aug-Sept: Half-strength balanced NPK every second or third watering. 

Light, July-Aug-Sept: 30% shade or less.

Temperature, April-May-June: Ambient daytime; about 5C at night. Miltonia and its hybrids will benefit from a higher night temperature.

Flowering: This group is rather variable in its blooming but flower stems are produced either from the base of matured growths or from partially developed new growths. Stake and tie the stems as necessary.

Miltoniopsis (pansy orchid)

Updates to come

Water, July-Aug-Sept: 

Fertiliser, July-Aug-Sept: 

Light, July-Aug-Sept: 

Temperature, July-Aug-Sept: .

Odontoglossum (crispum types)

Water, July-Aug: Water sparingly but ensure the mix stays damp but not wet. If in doubt, don’t water. Sept: Temperatures will be rising now so increase water but still let the mix become dryish between waterings.

Fertiliser, July-Aug-Sept: Half-strength balanced NPK every second or third watering. 

Light, July-Aug-Sept: 50% shade.

Temperature, July-Aug: Ambient daytime; about 5C at night. Sept: Ambient day; about 5-10C at night.

Flowering: These plants do not have a strictly seasonal blooming time as where they originate (near the Equator) they have no summer, autumn, winter or spring. Flower stems arise from the base of the newly matured pseudobulbs.

Oncidium dancing ladies types

Water, July-Aug: Water sparingly and allow the mix to become rather dryish before watering again. When in doubt don’t. Sept: Temperatures will be rising now so increase water but still let the mix become dryish between waterings.

Fertiliser, July-Aug-Sept: Half-strength balanced fertiliser every second or third watering. 

Light, July-Aug: 30% shade or less. Sept: 30% shade.

Temperature, July-Aug: Ambient day; about 5C at night. Sept: Ambient day; about 5-10C at night.

Paphiopedilum (slipper orchid)

Water, July: Very light and infrequent – enough to keep mix just moist (no more than that). When in doubt, don’t water. Aug-Sept: Gradually increase as warming temperatures allow. Proceed when mix is just moist at the base of the pot. When in doubt, don’t water.

Fertiliser, July-Aug-Sept: Half-strength balanced NPK.

Light, July30% shade. Aug-Sept: Increase shade up to about 60%.

Temperature, July-Aug: Ambient daytime; 10C at night. Sept: Ambient during day; 10-12C at night.

Flowering: When a bud is showing in the center of the plant try not to have water sitting there as this can cause the bud to rot off. When staking the flowers let the flower open and ‘set’ before bringing the stem to a fully erect position – this way the flowers will look up at you and stay that way.

Phalaenopsis (moth orchid)

Water, July-Aug-Sept: Often enough to keep the potting mix moist (not wet!) but allow the top layer to become dry looking before watering again. It is a good idea to use tepid water, especially during the colder months.

Fertiliser, July-Aug-Sept: Feed regularly, maybe every second watering, with half- to three-quarter-strength liquid fertiliser.

Light, July-Aug: 30-50% shade. Sept: 50% shade.

Temperature, July-Aug: 20-25C during the day; about 15C at night. Sept: 20-25C during the day; 15C at night.

Flowering: Keep developing spikes staked and trained.

Sarcochilus

Water, July-Aug: Reduce watering to suit conditions but do not let the plants dry out completely. Sept: Increase water as day/night temperatures rise.

Fertiliser, July-Aug-Sept: Half-strength balanced fertiliser every second watering.

Light, July-Aug-Sept: All roof shade cloth should now be removed. Try to give the plants give as much light as the plants were getting over the spring/summer period. This will improve flowering.

Temperature, July-Aug-Sept: Ambient during the day; 2-5C at night.

Flowering, July-Aug: Flower stems should be showing and in warmer areas developing well. Sept: Flower stems getting long enough to stake and train as you wish.

Other: Do not squash up your plants.