Question: I have a philodendron that has been sitting in the same spot in my front room for years, but lately it’s been a little droopy, with dried-up leaves. I haven’t changed the way I water it, so what could be wrong?

Answer: If your philodendron, or any indoor plant, has been in the same pot for several years, the soil is probably lacking nutrients. Regular watering washes the nutrients from the soil over time. Repotting your plant in fresh soil restores those nutrients and rejuvenates the plant.

The roots also might be pot-bound, also known as root-bound. When this happens, roots are constricted in a tight space and can’t absorb enough nutrients or water.

Whether it’s pot-bound or just needs fresh soil, we recommend the same treatment: repot your plant in fresh soil and in a slightly larger pot. For this process, our California Garden website (bit.ly/3zLZn3M) recommends you use potting soil developed specifically for plants grown in a pot, because soil in a container behaves very differently than soil in the ground. Potting soils are typically formulated with a high percentage of bulky organic materials such as bark, wood chips, peat or compost.

Whether you buy new potting soil or use the rest of a bag from last season, always check the soil moisture. Very dry potting soil can’t immediately absorb water. Pre-moisten the soil in a container by mixing water with the soil and allowing time for the water to be absorbed.

To determine the right size for the new pot, measure the diameter of the existing pot and find one approximately 2 inches larger. The size doesn’t have to be precise, but the plant does better if its roots are not swimming in the new soil of a much-larger pot.

The day before you remove the plant from the original pot, water it well. By the way, a philodendron’s sap is slightly toxic and can cause a skin rash. Wear gloves or frequently rinse your hands throughout the following process.

To remove the plant from its pot, turn the pot on its side, tap all around the side of the pot and tug a little on the plant. If you see a tight mesh of roots encircling the inside of the pot, with more roots than soil, your plant is pot-bound. Pull the plant completely out of the pot, then untangle and loosen the roots, including those winding around the bottom.

Massage the clump of dirt and roots to relax the root ball and release about half the original soil. Snip off the long, scraggly excess roots and trim off any roots that encircle the pot. Remove the dead or yellow leaves to reduce stress on the plant, and gently rinse dust and soil from the remaining leaves with the shower nozzle of your hose on a fine setting.

Next, cover the drain holes of the new pot with a fine-mesh screen, such as a coffee filter. To make sure the new pot is the right size, compare the size of the trimmed-up root ball to the size of the new pot. When the plant is in the new pot, the crown of the plant, where the stem meets the root ball, should be level with the soil surface and about an inch below the rim of the pot.

Fill the bottom of the new pot with soil, then place the plant on top of the soil. Remember to leave enough space between the soil and the rim of the pot so you can water it properly. You may have to lift the plant up to add or remove soil underneath until the crown of the plant is an inch below the pot rim when the plant sits in the pot.

Add soil around the sides of the root ball, using your fingers to gently massage the new soil into the root ball, then lightly tamp down the soil. Water the plant thoroughly to remove any remaining air pockets. If the soil level sinks, gently lift the plant, add more soil and tamp it down again, so you end up with the needed space below the rim of the pot.

The growing season for philodendrons and other tropical plants in our area is late spring through summer. You can repot them at any time, but the ideal time is either at the beginning of their growing season in the early spring or in the fall, when the plant is going into dormancy.

Also check out UC Marin Master Gardeners’ advice on caring for houseplants at bit.ly/3HWDf9z.

Q: A new California state law, SB1383, went into effect on Jan. 1. It requires residents to separate food waste from all other trash. Food waste is now supposed to go in the green bin, not the regular waste bin. But adding meat bones and other foods scraps to my green bin is creating a stinky, slimy mess! Can I put that food waste in compostable plastic bags and then add them to the green bin?

A: According to Zero Waste Sonoma waste management agency, the answer is no. You should not put “compostable” biodegradable plastics, including compostable plastic bags, in the green bins.

Most composting facilities in California, including Recology, Cold Creek Compost, WM Earthcare and Napa Recycling, do not put compostable plastics in their compost piles.

Facilities that accept compostable plastics have procedures to first pull out and send those plastic items to landfills before composting even begins, defeating all your good intentions.

As reported in The Press Democrat last week, compostable plastic packaging and utensils aren’t accepted because of synthetic binders and other issues, according to Zero Waste Sonoma Executive Director Leslie Lukacs.

So instead of using compostable plastic bags, Zero Waste Sonoma staff suggest wrapping your food scraps in newspaper, egg cartons or used paper towels before adding them to your green bin. If your neighbors are willing, you all could share one bin for food waste.

For more information, read how Recology and Zero Waste Sonoma explain the new composting law: bit.ly/333GWf0 and bit.ly/3zQHNLG.

Contributors to this week’s column were Laura Eakin, Karen Felker, Patricia Rosales and Debbie Westrick. Send your gardening questions to scmgpd@gmail.com. The UC Master Gardener Program of Sonoma County (sonomamg.ucanr.edu) provides environmentally sustainable, science-based horticultural information to Sonoma County home gardeners. The Master Gardeners will answer in the newspaper only questions selected for this column. Other questions may be directed to their Information Desk: 707-565-2608 or mgsonoma@ucanr.edu.