The days are getting warmer. Your plants are perking up with longer daylight hours. You wish to provide the best environment for your plants (they have the same wish)!
We're here to set your mind at ease and help ease your plants into the exceptional Canadian Spring/Summers we have!
Here are a few things you can do to make the transition a success!
Your plants need to 'harden off', so go gradually!
If you're growing plants without supplementing light, your plants have been mostly dormant during the winter. They know when they're not getting enough light, and their growth slows down to reflect that. They need to wake up (or harden off) to be able to withstand outdoor conditions!
This also means your plant leaves are not used to the sun without the filter of glass! Regular-degular glass, typical in windows, blocks a lot of UV rays. Plants that love bright, direct sunlight generally make their own 'sunscreen' (called anthocyanins), but it takes time!
To get your plants ready for the summer outdoors, start in the mid to late spring, and introduce your tropicals outside in full shade. Over the course of a few weeks, slowly inch them into morning light (East).
The harshest sun is South and South West, so ensure you are not letting your plants sit in the harsh sun if they are NOT full sun varieties. Most Colocasia, Alocasia, Succulents and Hoya love full sun. Monstera, Philodendron and other Aroids tend to grow under tree cover so grow them in shadier locations or under gazebos and awnings.
Remember, an overcast day still has better light quality than most artificial lights! This means that direct sunlight can obliterate your plants if they're not ready!
Check for pests.
Houseplant pests outside aren't such a big deal as they tend to get eaten by natural predators, but you definitely don't want to bring the enemy inside to wreak havoc on the rest of your collection.
Start by giving each of your plants a really good visual inspection. Check the top and bottom of leaves, stems, and soil. If you spot a pest, now's the time to stop them in their tracks.
Mix a couple drops of dish soap and a splash of peroxide in a spray bottle filled with water, spray your plant all over and wipe it down thoroughly to remove any traces of pests and larvae/eggs, which can be trickier to spot. You will want to repeat this a few times as you get ready to move your plants inside to make sure they've gone.
For plants where you're not seeing any pests, it can be helpful to just give them a good rinse off anyhow as a precautionary measure.
During the transition period, when you do moving your plants form inside to out, and back in again, try to keep them separate from your indoor only collection. This transition can be stressful and pests LOVE a stressed plant. Repeat the same treatment above if you spot any hitchhikers.
Prune and re-pot.
While your plants are outdoors, now is the perfect time to make a mess! Whether your plants need a bit of a haircut or they've outgrown their pots, take advantage of the weather to do this outside where you'll have a lot less cleanup.
Prune back any damaged foliage or spent blooms. Pruning before the growing season can help jump start an excellent growing season. Don't forget to prop your cuttings to fill out your plants!
If your plants are in need of a bigger home, use this time to help them move in! The general rule of thumb is to move up 1-2" in pot size, ie. move your 4" plants into a 5-6" pot. This will also make your spring/summer transition a little easier next year as these plants shouldn't need to be repotted again for a couple years. Future you will be grateful!
Adjust plant care.
Moving into spring, your plants will start drying out more quickly. You can start to increase your watering now as well as fertilizing if you stop feeding over the winter. Make sure you are paying close attention to your plants and their changing needs during this transition.
Tip: Use a chopstick! Pretend you are baking brownies and insert a chopstick into the soil at the center of your pot. If it comes out clean, your plant is dry and likely needs water. If it comes out covered in "crumbs" ie. bits of soil, your plant is still moist beneath the surface and may not need water. Some plants want to be much drier than others before their next watering.
This transition will take a few weeks. Your plants will be safe outdoors 24/7 ONLY after nighttime temperatures rise to at least 10°C. Keep an eye on the weather! Any nights (or days) close to 5°C, and you may want to bring your plants back inside to avoid potential cold/frost damage.
I hope these tips help you enjoy a smooth transition as you bring your plants outside after the Winter!