Philodendrons are the plant that makes new growers feel competent and experienced growers feel understood. They are forgiving without being boring. They grow visibly, respond to good light, and tell you clearly when something is wrong — which is more than most houseplants will do.
The one leaving here is a heartleaf philodendron (Philodendron hederaceum), propagated from a cutting taken in this house, rooted in water, and potted into soil once the root system was ready to support it. It is already growing. Your job is not to fix it; it is to keep it going.
Light
Bright indirect light is the sweet spot. An east-facing window, or a few feet back from a south or west exposure. Philodendrons tolerate lower light better than most aroids — they will survive a dim corner, but they will grow slowly and the leaves will get smaller over time. Give it decent light and it rewards you with large, rich leaves and quick new growth.
Water
Water when the top inch of soil goes dry. In a 4-inch pot in a bright spot, that is probably every five to seven days in summer, less in winter. The philodendron will begin to droop slightly when it is thirsty — that droop is a request, not an emergency. Water thoroughly, let it drain completely, and empty the saucer so it is not sitting in standing water.
Overwatering is the most common way to kill a philodendron. When in doubt, wait another day.
Humidity and temperature
It prefers humidity but handles normal household air without complaint. It does not want to be near a heating or air conditioning vent, or against a cold window in winter. Room temperature — anywhere between 60 and 85°F — is fine.
Feeding
A balanced liquid fertilizer once a month during the growing season (spring through early fall) is enough. Skip it in winter. This plant does not need to be pushed.
The climbing thing
In the wild, philodendrons climb. Given a moss pole or a piece of bark to hold onto, the heartleaf will produce larger leaves and grow faster. It does not require one — it will trail happily from a shelf or a hanging basket — but if you want to see what it can really do, give it something to climb.
What to watch for
Yellow leaves usually mean overwatering. Small or pale new leaves usually mean low light or no fertilizer during growing season. Brown tips can mean low humidity or inconsistent watering. All of these are recoverable; none of them are emergencies.