Why are my okras not growing, and can rainwater be used to water plants? Demystifying common problems for first-time plant parents
BY RACHEL QUEK, 29 APRIL 2022
Light, water, and soil – are these the only ingredients for your plant’s healthy growth? Experts say the winning formula is to first understand their characteristics
If you have adopted your first house plant – congratulations, you have become a plant parent. And just like any parent, you now find yourself spending a lot of time checking if your child is thriving, and consulting “Dr Google” for answers to all your questions.
To aid your plant parenting journey, we compiled a list of common questions from our very own gardening enthusiasts at DBS and consulted two expert horticulturists from the National Parks Board (NParks) for some answers.
Top 10 tips we gathered, and answers to some common questions!
Bask in the right amount of sunlight
Besides singing to your plants to encourage them to sprout, taking note of how long your plant is exposed to the sun and the light intensity is essential for their healthy growth.
Tip #1: Edibles need direct sunlight
Most edible and flowering plants need direct sunlight, for about four to six hours daily. However, if you have space constraints and need to grow them indoors, place your edible plants close to a window with direct sunshine.
Q&A: “My lime plant stopped growing after a while even though there are still leaves. How to spur it to the next stage of growth?”
Dr Wilson Wong, Deputy Director, Jurong Lake Gardens: Sun and soil are two essential ingredients for a healthy plant. If your lime plant is getting enough sunlight and water, check its soil as well. I always recommend focusing not only on the plant’s surface but also to observe its soil. An overly compact or wet soil may affect a plant’s roots and its ability to absorb oxygen for good health.
Tip #2: Foliage plants are great for indoors
They are low-maintenance and can grow in areas with indirect light. If your home lacks the right amount of sunlight, consider using artificial grow lights. Most grow lights need to be switched on for about 12 hours daily and placed at least 15cm away from the plants depending on the light’s intensity.
Tip #3: Rotate for an even growth
As plants grow in the direction of sunlight, rotate your potted plants occasionally to get more balanced and luscious growth.
Monitor surrounding humidity
Too much moisture in the air can lead to fungal and bacterial infections in plants. Watch out for common infection symptoms such as leaf spots and powdery mildew.
Tip #4: Edibles thrive in ambient humidity
Edible plants grow best under sunlight, with normal ambient humidity. However, if they are exposed to excessive winds, such as at balconies located at high levels or in an air-conditioned environment, they may experience excessive drying and become prone to spider mite infestations.
Tip #5: Create humid conditions for tropical foliage plants
Meanwhile, tropical foliage plants, with origins in rainforests, require a high humidity environment. Create a microclimate for tropical foliage plants by using misters or grouping them as the moisture from transpiration can increase and maintain a healthy ambient humidity level.
Q&A: “My okra plant, grown indoors, is not bearing fruit and has black spots on its leaves. How do I treat these spots?”
Dr Wong: It is challenging to grow okra, or ladies' fingers, indoors as they need a lot of sunlight and good air circulation. Meanwhile, the black spots on your plant’s leaves are signs of fungal infection. You can prevent such infection by spraying diluted milk – a common home remedy – on the leaves to reduce the incidence and severity of fungal infection.
Drink enough water
While humans are recommended to drink about two litres of water a day, plants only need moist soil to grow well. Overwatering your plants will suffocate and drown them as they need their roots to breathe.
Tip #6: Check the soil’s moistness level
Only water your plants when the soil beneath the surface feels dry. Insert your finger or a chopstick 1cm into the soil’s surface to determine whether it is moist enough.
Tip #7: Practice deep watering
When watering your plant, ensure the soil is soaked about 7 to 10 cm deep so that water is readily available to its roots.
Q&A: “Can I use rainwater to water my plants?”
Ms Vicky Lim, Manager, Nursery Management, NParks: You may use rainwater to water your plants if you do not live near an industrial estate as chemical content in the rainwater may damage your plants. You are also not encouraged to use the water from washing rice as the starch may harden the plant’s soil and encourage fungal and bacterial growth.
Pests and other infections
Nothing makes a plant parent more anxious than a plant that looks weak and diseased, often due to unwelcomed pests and bacterial or fungal infections. These pests suck nutrients from the plants and inhibit their growth.
Tip #8: Spot the signs of uninvited pests
Common plant pests such as mealybugs and spider mites may make a home on your plants’ stem, roots, and the underside of leaves.
Spider mites feed on leaves and their damage often appears as black or red spots on leaves. When dealing with spider mites, handpick and destroy affected leaves at once or spray insecticides such as Starxle G and Imidacloprid.
Root mealybugs, on the other hand, suck the sap from roots and causes a plant’s health to deteriorate. The first sign of a mealybug infestation is yellowing leaves and can be treated by repotting the plant and replacing existing soil with fresh sterilised ones.
Tip #9: Sanitise your hands!
Make sure to wash or sanitise your hands after handling an infected plant as the disease can spread from one plant to another when handled simultaneously.
Q&A: “How to protect my plant from pests?”
Ms. Lim: You can place a mesh or netting, with a hole size of about 250 microns, around your plant to protect it from insects while ensuring it gets sufficient sunlight, air, and moisture.
Tip #10: The power of fertilisers
Fertilisers, or plant food, are applied to the soil to increase fertility in plants so that they can grow vigorously and reproduce. The macronutrients in fertilisers – nitrogen, phosphorus, and potassium – promote the growth of leaves, roots, flowers, and stems as well as increase the plant’s resilience. Common signs of nutrient deficiency in plants include stunted growth, yellowing of leaves, and burnt appearance on leaf tips.
Q&A: “What should I add to my edible greens to make them luscious? My Chye Sim has skinny stems and small leaves.”
Ms. Lim: Apply fertiliser to your plants when they are hydrated to ensure they have the right nutrients. Make sure to apply diluted fertiliser at a higher frequency to avoid stressing out the plant.
Some of these practical gardening tips were crafted in response to questions by DBS’ plant parents who received free seed packets from the NParks’ Gardening with Edibles initiative. The programme – supported by DBS Bank – was launched in 2020 to cultivate a culture of gardening and support our national strategy to strengthen food resilience. Over 860,000 seed packets have been distributed to households across the country.
For more tips on urban gardening, check out other articles below:
