All of these plants are in one area of my home which is in front of a large window that is north facing and there is also a grow light which is on from 8am-5pm. I also run a humidifier for about 3-5 hours per day. I live in Canada so it is winter here now but I do not open the window near the plants

To my old eyes, it looks like they are all suffering from lack of sufficient water.

Yes, the soil looks really dry.

that was my first thought. Very dry. Not enough water and probably not enough light at the north window, despite the grow light. It's hard to balance watering and light needs in the winter.

If the grow light is too far above the plants, it basically does nothing.
I agree with everyone else, you need to water your plants!!!

Grow lights only ever do nothing if you forget to turn them on. But their effectiveness greatly reduces with every inch of distance between the bulb and the plant's leaves.

Too dry, my gosh (only the succulents can handle that).

Watering with a can isn't going to be sufficient anymore. When potting soil dries out that much it becomes hydrophobic and thus repels water.
You need to submerse the pot in a bucket and let it soak up water for as long as it takes. Then let it drip out over the next few hours and you're good to go.

Now I'm visualizing the times I've put a pot in a bucket of water just to have the plant bob up and float away out of the pot.

DaisyI said:Now I'm visualizing the times I've put a pot in a bucket of water just to have the plant bob up and float away out of the pot.

Trust me, we've all been there and though we know the answer, we rarely do it right: put something heavy on it

Thank you everyone! I water them once every 1.5-2 weeks because before I had plants that all suffered from me over watering them! It's tricky. They have been thriving for about 8 months now all the sudden this is happening
What is a suggestion for how often to water?

ktcouvs said:Thank you everyone! I water them once every 1.5-2 weeks because before I had plants that all suffered from me over watering them! It's tricky. They have been thriving for about 8 months now all the sudden this is happening
What is a suggestion for how often to water?

Experience really. Or sticking your fingers in there to have a feel. Not all plants require the same watering regime + it depends on light, temperature, humidity (evaporation) and air movement....all these factors contribute to evaporation and transpiration.

Except for the Euphorbia (plant in the background in 3rd photo), your plants will all appreciate being damp. Not wet, damp. That means when you stick your finger in the soil, when its dry an inch down, water. Don't let the pots sit in water. Pick the pots up and feel their weight. After you water, do it again. They should weigh quite a bit more. If you are deciding when to water, pick up the pot and see how much it weighs.

You can also check for moisture at the bottom of pot by pushing a bamboo skewer into the soil to the bottom of the pot. Leave it for a minute and pull it out. How does it feel (wet, damp, dry).

You can tell they are very underwatered as all the soil has pulled away from around the edges of the pot.

Thank you everyone! I water them once every 1.5-2 weeks because before I had plants that all suffered from me over watering them! It's tricky. They have been thriving for about 8 months now all the sudden this is happening
What is a suggestion for how often to water?

A watering schedule (how often to water) depends on the type of potting medium in use and how quickly it dries out. The soil should be thoroughly saturated until water is freely exiting the drainage holes and the pot should be allowed to drain before placing it back on it's saucer. The soil moisture can be checked again in five to seven days by sticking a finger down a few inches into the soil. If it's still moist/damp, hold off on adding additional water and check again in another couple of days. The plant roots should be kept barely moist, not sopping wet to the point where they rot but not so dry that the roots wither and die. It's all a learning experience with getting to know the type of plant, it's growing requirements for light, temperature and moisture, etc. and paying attention to the soil and how quickly it dries.

To my eyes, the soil in your photos appears to be quite dense and water retentive, which would allow the plants to go longer periods between watering but you say you water every 1.5 to 2 weeks which makes me think you are not watering thoroughly enough to saturate the soil and roots.

ktcouvs said:Thank you everyone! I water them once every 1.5-2 weeks because before I had plants that all suffered from me over watering them! It's tricky. They have been thriving for about 8 months now all the sudden this is happening
What is a suggestion for how often to water?

It is impossible to tell a person how often to water. I would have to be onsite to tell you. I live in a wood heated house in Canada. I don't use a humidifier. I primarily grow cacti and succulents but other types of plants as well. Most folks will tell you not to water cacti in the winter but given my conditions I water most of mine (about) every 2-3 weeks. When the pot feels light or the plant is getting soft. I have a ZZ plant that I only water about every 6 weeks (they have water storing parts like a camel). My clivia only gets water about every 4 weeks. The gal I saved it from had almost killed it with water. You need to develop a sense for when watering is necessary. It's an art. I keep most of my plants under HID metal halide lights for 16 hours a day and my cacti, which many folks quit watering and let go dormant through the winter, continue to grow. One thing I can tell you is more light is the best thing you can do for your plants.

Water, run the humidifier longer.

These look so dry, though, that the roots may be dead. Put water in your bathtub and stand these in there for an hour or more. The water should be about half way up the pot. If you pour water on top now, it will just flow down the sides and not wet the substrate at all. Could be what happened in the first place. They got too dry once, you watered and thought they were OK, but basically, they got no water at all.