Pink houseplants are all the rage and the philodendron pink princess (PPP) is one of the hottest variegated plants. The colors and variegation vary greatly depending on maturity and environmental conditions.
The most common question I get regarding philodendron pink princess is: "How do I get more pink?". There's no simple answer; however, I will cover a few tips that have worked for me.
SOIL: Make sure your PPP is planted in well-draining potting soil. I personally just eyeball my potting mixture. I mix roughly 65-70% Miracle Gro Indoor Potting Mix (or if you're feeling fancy, Fox Farm Ocean Forest potting soil) with 20-25% perlite, and 10% horticultural charcoal. I also sprinkle Systemic Insect Control granules in my mix, but that is optional. I've found that PPPs like to be on the drier side, so let the soil dry out a little between watering. If you're worried about over-watering, make sure to use a terra cotta pot. Always plant in pots with drainage holes.
LIGHT: Make sure your PPP is getting bright light, but not direct sun. I've found that brighter light encourages better foliage colors and increases variegation. Note that variegation in the plant itself can be a bit unstable, so there's no fool-proof way of predicting variegation. We can only help it by giving what the plant prefers, which is bright light.
HUMIDITY: The humidity in my house is usually between 60-65%. Many philodendrons prefer higher humidity, especially when unfurling new leaves. If the humidity is too low, new leaves may tear or become stuck or deformed. If you notice a new leaf that may be having trouble, you should increase the humidity. An easy way to do this is to mist the plant or place it in a humidity dome or clear plastic bag. You can also run a humidifier that will raise the humidity levels of your room. You can measure your humidity levels easily with this humidity meter.
The maturity of the plant plays a factor in the appearance of PPP leaves. I've found that younger plants tend to have narrow, greener, and light pink leaves. As the plant matures, newer leaves grow wider and larger. The more mature leaves tend to be darker and have hotter pinks.
Sometimes a PPP can have very low variegation or possibly revert. You can check the stem of the plant to see if this is the case. The photos below are stem comparisons. The stem on the left is from a highly variegated PPP and the one on the right is a PPP with low variegation.
If you find that your PPP may be reverting (loosing variegation), you can cut it back to a more variegated section of the stem. This will encourage the new growth to be more variegated. When cutting, make sure to use clean/ sanitized shears. Treat the cut with some cinnamon powder to prevent infection/rot.
You can also propagate cuttings by dipping them in rooting hormone powder and rooting it in water. I personally prefer to root most cuttings in LECA Expanded Clay Pebbles (AKA forbidden Cocoa Puffs) with water. If using the LECA method, make sure to rinse and soak the pebbles before using. Place your cutting in a glass and fill it with the LECA to cover at least a node on the stem, then fill with water. I usually keep the waterline the same as the height of the LECA in the glass. I'll top it off with clean water if the water level gets low.
Remember that it takes a lot of time and patience to grow a specimen plant. Don't get discouraged if your plant isn't looking her best. It might take some trial and error to make your plant happy. The highly variegated PPP specimen you see in the photo was grown from a three-leaf cutting, and lost some leaves along the road to her current glory. The process was long but very rewarding!
SPECIAL NOTE: If you have questions regarding where to obtain a PPP or other rare plants in the U.S., please read the blog entry: A Guide to Unicorn Plant Hunting