My orchid won't bloom. What is wrong?

Okay so you successfully repotted your orchid and it is the following season and your orchid will not bloom!! What is up with that? Most likely your orchid is out of balance in either light, roots, growth, season and/or natural stimuli. Here are a few reason why this may happen;
1. Maybe it's light. Hands down the most common reason that orchids fail to bloom is insufficient light. My Phalaenopsis orchids are usually happy with the filtered light in my windowsill but many other varieties need more light. Dendrobiums, Oncidiums, Cymbidiums and other types of orchids need much more light. They may need supplementary grow lights, which I don't use…. I just put them in a brighter window.
You can normally tell if your orchid is getting too much or too little light by looking at their leaves. Below is an example of what a Phalaenopsis orchid leaf should look like with the correct amount of light. It should be shiny and bright green.
You may ask, “What will your orchid look like with too little light?” The leaves will be a dark forest green instead of bright green. Below is an example of this…

On the other hand unlike a tomato plant, they can't handle full sun. A bright window has much more shade then if they were outside. Windowsill light is called “dappled light” and works well for most orchids.
You may ask, “What will your orchid look like with too much light?” The leaves will be a light yellow-green instead of a bright green. They can also get sunburned… Both are shown below. You can see the yellow leaf and the scorching on the other leaf, from too much sun (which looks like a big brown spot).

2. Maybe it's the roots….
Orchids work in balance between their roots, leaves and blooms. If your roots are healthy you should get good blooms. Many times I have seen a gorgeous orchid with deceptively beautiful leaves and flowers but when I went to repot, I found a horrible root system. In this situation even though the leaves and flowers were pretty the plant would surely die (or would have really suffered) if not repotted.
Horrible root systems are linked to overwatering and/or lack of repotting. You orchid roots need ALOT of oxygen to survive and thrive. Without oxygen orchid roots will smother and die. It helps to have pots that you can clearly see their root system (shown below). Your orchid should have healthy green roots, as shown freshly watered below, on the left. In between watering they will look like the picture on the right a slight white/green which is also good.

Orchids are different from normal house plants….you can't plant an orchid in normal soil, they need unique soil. I get all my soil/mix from rePotme. And even their mix, which I think is the best, will break down over time and will need to be replaced through repotting. Orchid mix will always need replacing because orchids need fresh mix to thrive. Orchids will not have enough energy to bloom if their roots are suffering. Remember its a balancing act!
3. Maybe it's new growth… There are two types of growth patterns for orchids; sympodial and monopodial.
Monopodial orchids; Phalaenopsis (which I have ALOT of) and Vanda are the most common. They grow off a single central stem with leaves on either side. Each leaf should be at least as big as the leaf before it. There should be at least one or two new leaves per year.
You should look for the next bloom spike on monopodial orchids from the base at the underside of a leaf (usually 2 or 3 leaves down from the newest leaf) and on the opposite side as the prior bloom spike.
In order to keep blooming over the years, monopodial orchids such as Phalaenopsis need to put on new leaves each year. Over time, as the orchid grows in size and strength it will send out a bloom spike on each side of the stem simultaneously.
Sympodial orchids; These orchids have multiple growths and should grow 1 or 2 new growths per year. A newly acquired orchid may have 4 or 5 stalks, most with leaves, with the bloom coming from the largest stalk. The “stalks,” on these orchids, are called “pseudobulbs.” If your orchid is thriving you should see a new pseudobulb emerge from the base of the previous pseudobulb near where the orchid bloomed. During the leaf and root growth period (not the bloom period), usually in summer, this new pseudobulb will ideally grow to be at least as big or bigger than the one that just bloomed. The next bloom spike will come from this new pseudobulb. You should be looking for your orchid to grow big, healthy new pseudobulbs because they will be the source of the next season's bloom. Good light, fertilizer and water are also keys to healthy new growth. Over time, as the orchid grows in size and strength it will grow multiple pseudobulbs which can all spike at the same time creating an abundance of gorgeous flowers!
4. Maybe it's the season….Orchids naturally, bloom on their own schedule. Most likely it will not be the time of year it bloomed when you bought it because it was forced (off-cycle) into bloom at a nursery. You will find that most orchids grow new leaves and new roots during the summer, grow spikes in the fall and bloom in the winter through spring.

Most orchids will only bloom once a year but some bloom twice or more. Your blooms can last weeks or months while others can last only days. Some basic research about the type of orchid will identify what to expect. My Phalaenopsis orchids usually bloom once per year and their blooms can last for months. Once their flowers have fallen off they may have a couple of extra flowers emerge from the end of the bloom spike and bloom again but this has been rare for me. I also have Dendrobiums, Oncidiums and Cymbidiums- they usually bloom once or maybe twice per year with spectacular blooms that last a month or two.
5. Maybe it's natural stimuli – in nature, orchids have natural stimuli that indicate to the plant that the growth season is over and it's time to bloom. The two main characters of natural season are a dip in temperature in the Fall and gray days resulting in lower light. Some orchids are temperature sensitive and some are light sensitive.
Orchids that are sensitive to temperature are triggered to bloom by the natural cooling that occurs in the fall. This drop in temperature signals to the orchid that the growth period (new roots and new leaves) is coming to an end and it is time to get ready to set a bloom spike, as shown below. If your like me, you grow your orchids inside where the temperature is fairly constant. If this is the case, orchids can be deprived of the natural cues and will be reluctant to bloom. You will need to trick your orchid into realizing its Fall by giving it temperatures in the 60's for a brief period (1-2 weeks). You can do this by cracking a window near them. I found this very successful with my orchids.

Orchids are also sensitive to light and can have their natural cycle disrupted by leaving lights on, after dark, in our homes. As much as possible turn the lights off, at night, when your orchids are in your homes.
Hope that Helps,
Hannah
Feel free to leave comments or questions.