Vanda orchid care: getting a spike

[FreelanceFaye]

Alright, who do I sell my soul to? I've had one vanda for well over a year (Robert's Delight) and a second vanda from the same nursery. They live outside in the summer under an umbrella in the Deep South with ample humidity.
And exposed roots. They get dunked in my fish tank for 15-20 minutes every day when the temps are this high. They seem healthy. Great fat spongy green roots, spitting out leaves like no tomorrow, but no spikes.

Recently tried a different fertilizer, "bloom formula" 6-30-30. 1/2 tablespoon in a half gallon bucket. How often did you fertilize to get yours to bloom?

[fishmom]

Is your umbrella opaque? The most common reason for lack of blooms is lack of light. Many vandas get a tinge of red or pink when they are getting high enough light. How is the coloring on your leaves?

[bil]

Mine gets 50% sun, and Ray's KLite, which is a high nitrogen fertiliser at a very low dose.

These pics are January this year two spike, and later this year 3 spikes.
It currently has two more showing, s that's 7 spikes so far this year.

[FreelanceFaye]

Originally Posted by bil

Mine gets 50% sun, and Ray's KLite, which is a high nitrogen fertiliser at a very low dose.

These pics are January this year two spike, and later this year 3 spikes.
It currently has two more showing, s that's 7 spikes so far this year.

Wow beautiful!! 😍 How can I tell if mine are getting 50% light? They are a lovely Kermit the frog green but I worry light is a factor

[NYCorchidman]

How big are the plants?
Fertilizers do not make plants flower.
It just provides some raw materials for the plant to do what they need to do.

If they are of blooming size and the conditions are right, it's just a matter of time.

Given your description, you are growing them well.

[estación seca]

You can read about growing Vandas in south Florida on the Motes Orchids Web site.

[FreelanceFaye]

Originally Posted by NYCorchidman

How big are the plants?
Fertilizers do not make plants flower.
It just provides some raw materials for the plant to do what they need to do.

If they are of blooming size and the conditions are right, it's just a matter of time.

Given your description, you are growing them well.

They are pretty stacked, 16-20 leaves tall for each. Both have spiked twice in the past, not with me, but I see the base of the old spikes inbetween the leaves.

My boyfriend kindly reminded me it's been over two years since my purple Vanda Spiked (pictures of the flowers in spring 2015.) So it sounds good on paper, but there's something I'm doing that not right.

[fishmom]

The most accurate way to judge the amount of light is to use a light meter, but if you don't want to get that, you can look at the shadow of your fingers on the leaves. A sharp shadow means bright light, a fuzzy shadow with distinct fingers would be medium light. Vandas need bright light. Check it when the sun is overhead to see how much light is getting through the umbrella.

Can you post pictures of the leaves and of your growing location?

[estación seca]

To sum up:
Martin Motes recommends watering every day, twice on hot dry days. The roots must be thoroughly soaked, and change completely from white to dark green.

He recommends heavy feeding, to ensure maximum leaf production, because each leaf axil can produce an inflorescence. Motes writes there should be a pale green zone 1 centimeter wide at the bases of emerging leaves when they are fertilized properly. If the zone is absent, or less than 1cm wide, increase fertilizer. If wider than 1 centimeter, decrease fertilizer.

He has written he uses between 1-3 tablespoons of 20-20-20 fertilizer with micronutrients per gallon of water. This is 15-45ml of powder per 3.78 liters of water. He uses this every 5th watering. Later I read he had decreased his fertilizer concentration since reading the Michigan State reports, but he still aims for the 1 cm pale green zone on developing leaves. He still fertilizes every 5th watering. In a lecture I have heard Bob Fuchs of RF Orchids say the same thing about fertilizer type, and feeding frequency. Bob said he currently uses 2 Tablespoons (30ml powder) per gallon.

Motes recommends supplemental feeding with magnesium sulfate (Epsom salts) through the year, during a watering that does not include other fertilizer. He doesn't give a dose. He writes Vandas do not show magnesium deficiency during the warm season, but they do not grow and bloom as they should. During cooler seasons magnesium-deficient Vandas develop extensive red pigmentation of the leaves. It can take months to replenish magnesium in deficient plants. Many plants imported from overseas are magnesium deficient, and turn red their first winter in temperate zones.

He recommends high light, such that the leaves look like a yellowish Granny Smith apple. This is much more light than most people give Vandas, because they don't get enough sun or because the plants might burn without adequate air circulation.

And, in his high-humidity climate, he recommends regular treatment with antifungals and pesticides (to kill thrips.)

I will expand a little on the above, based on my experience growing Vanda seedlings in a hotter and drier climate than South Florida.

A dry, wrinkled Vanda is not likely to produce flowers. I visited RF Orchids in south Florida in November. They water first thing in the morning. Their Vandas' roots were still partly wet in early afternoon. In Florida the plants take up water for a long time after each watering.

My plants' roots are completely dry within an hour of me watering them. My plants could not take up water for hours afer a morning watering, like plants in Florida can. I realized that, in my lower-humidity environment, I need to do more watering than just soaking my plants' roots twice a day. So, I grow my plants bare-root in vases, and I water by filling the vases, and soaking my plants' roots in water for 12-24 hours each watering. My problems with leaf dessication (fine linear wrinkles) and root death have disappeared with more watering.

During the summer I would do this every night, if I had time. In the cooler winter a soak every 3-4 days is sufficent for my plants. In my lower-humidity environment I have had no rot at all. Unfortunately, in summer I cannot water as much as I would like. I need to get up in the morning and go to work (until I can find somebody who will keep me in style.) On weekends when there is not high summer heat, I will fill the jars with water during the day and set them outside, with a fan blowing directly on them to keep the leaves at ambient temperature. With the fan, and jars full of water to absorb heat, even in hot Arizona sun, there is no leaf burn at ambient temperatures up to about 100 F / 38C. I don't leave my plants soaking overnight outside due to critters which will eat them.

At first I was terrified of using as much fertilizer as Motes and Fuchs recommend. This is vastly more fertilizer than most people use on orchids. I have been gradually increasing the concentration. My plants grow better and better with each increase.

But remember something! Plants can only use fertilizer if conditions are otherwise adequate for growth. In warm, sunny situations, like mine and that in South Florida, plants will be able to use a lot of fertilizer. In a much cooler situation they will not grow as fast, no matter what you do. So the Motes recommendation, to maintain a 1cm pale green zone at the base of emerging leaves, is something people can use to calibrate their fertilizing, no matter the other growing conditions.

As for magnesium sulfate, I add it to my soaking water for all waterings that don't include fertilizer. I am using 1 teaspoon of Epsom salts per gallon of water / 5ml powder per 3.78 liters. During the soaks salt crystallizes on my plants' leaf surfaces, especially near the leaf bases. This assures me the plants are taking up magnesium. I have not seen any signs of burning from the Epsom salts. Fertilizer burn has been a problem, however... keep reading.

I noticed that, when soaking my plants in fertilizer solution, it evaporates down below the level of the uppermost roots. As water evaporates from the upper roots, fertilizer salts concentrate there, and kill them. I stopped increasing the fertilizer concentration when I noticed this. Now I make sure plants soaking in fertilizer solution with a fan blowing on them have the water level well above the lowermost roots. Many of my plants are now mostly submerged during soaks. I have not had any rot with soaks of up to 24 hours.

Now that I will be able to avoid root burn from fertilizer evaporation, I will resume upping my fertilizer concentration, because I have not had the pale green zones on emerging leaves reach 1cm consistently. I am currently using 1 teaspoon / 5ml of 20-20-20 powder per gallon of water. I will increase that every watering until I get the right pale green zone on emerging leaves.

My summer daylength is slightly longer, and winter daylength slightly shorter, than Motes', but my sun intensity is more than adequate for Vandas all year, even through a window. This is not the case at higher latitudes. High light intensity is not easy to achieve in winter indoors, nor during the summer at higher latitudes. When it's too cool outside, my plants are in a 20-gallon / 75 liter aquarium with a glass top, under 2 spiral CFL bulbs, 6500K, 40W (200W equivalent) in aluminum reflectors. Most of my seedlings are still too small to bloom, but this is adequate winter light to have bloomed one of them. On warm winter weekend days I put them outside for the sun.

In my lower-humidity growing rooms (40%-70% RH) I have not had any problems with fungus, nor with thrips. I have lost spikes that formed under my care because I did not water enough. I am still trying to figure out how to give more light without burning the leaves. I suspect soaking my plants will kill any thrips that might arrive with them.

[bil]

Interesting post. The problem I have is that if I use a stronger level of fertiliser, that dries on the roots and burns them. I damn nearly killed mine last year doing that.
So, I stick to a much weaker solution.