There are several factors that must be considered before determining the appropriate watering frequency for your plants. These factors includes:
Yellowing or browning leaves could be an indication that the plant is stressed. The causes of yellowing or browning leaves can vary and can be attributed to:
Nutrient deficiencies of nitrogen, magnesium and iron, which often show up as distinct general or interveinal chlorosis of young and/or old leaves
Underwatering; usually with wilting symptoms before leaves turn brown and fall off
Overwatering; usually as yellow to brown edges with leaves hanging on the plants
Sun damage; as white spots or patches, or crispy brown leaves
Temperature stress i.e. too hot, too cold
Over fertilisation, causing leaf-burn
Pest attacks; usually due to sap-sucking insects e.g. aphids, spider mites
Diseases e.g. fungal or bacterial infection, with soft mushy tissues and smell
Fret not, if only a few of the bottom leaves turn yellow or brown, it’s usually natural. These leaves turn yellow as the nutrients are re-distributed for the production of new shoots or leaves.
Mealybugs, which appear as white cottony substances, and scale insects, which are small brown spots, are common pests that are typically found on the stems or underside of leaves. These insects can harm the plant by using their piercing mouthparts to suck sap, which deprives the plant of nutrients and can stunt growth or cause leaf distortion.
To eliminate mealybugs and scale insects, you can manually remove them with a blunt object e.g. cotton bud or sponge if the infestation is minimal, or use insecticides like neem oil and white summer oil for serious infestations.
Ants might be a nuisance but they don’t directly harm your plants. Their presence on your plants could be due to:
Nesting in the planting media such as soil or charcoal of your potted plants
Presence of sap-sucking insects such as aphids, which the ants farm for their ‘honeydew’ - excess sugar-rich droplets after feeding
To eliminate ants, you can either use ant bait or get rid of the sap-sucking insects. A diluted mixture of natural tree oil or white vinegar might be a cheaper alternative to deter the ants.
There are a few shade-tolerant plants available as houseplants. A few options include:
Heartleaf Philodendron (Philodendron hederaceum)
Money Plant/Golden Pothos (Epipremnum aureum cultivars)
Chinese evergreen (Aglaonema species & cultivars)
Flamingo Lily (Anthurium andraeanum)
Prayer plants (Calathea, Goeppertia & Maranta species & cultivars)
Metal Palm (Chamaedorea metallica)
Parlour Palm (Chamaedorea elegans)
If these choices don't tickle your fancy, consider browsing through the NParks Flora&FaunaWeb (Flora Fauna Web) for more choices.