Marigolds are stunning annual houseplants that are popular and primarily grown for their beautiful flowers. These flowers are typically orange, yellow, or red and are typically densely packed on the plant’s shoot or solitary, depending on the marigold species you’re growing. However, like with every other houseplant, you might encounter a few issues getting the plant to grow tall.
You can fix marigolds that aren’t growing tall by moving the plants to a spot where they can get enough sunlight. Other strategies include ensuring that you use well-draining soil, controlling humidity levels, ensuring the temperature isn’t too high, and optimizing your watering practices.
While marigolds can reach a maximum height of between 6 inches and 5 feet (15 and 152 centimeters), yours might struggle to grow tall. I wrote this article to serve as a complete guide for gardeners dealing with underdeveloped marigolds, and you’ll learn quick and easy solutions to make your plant thrive. Let’s get started.
1. Move the Plant to a Spot It Can Get Enough Sunlight
All green plants use sunlight to perform photosynthesis and create energy for their life processes. They use this energy provided by the sun to grow deeper roots, bloom, and develop extensive shoots. However, these plants require this sunlight in specific amounts—too little, and they don’t grow tall; too much, and you risk burning them.
Marigolds need at least six hours of sunlight to thrive, but they also prefer to stay under the sun. And while most houseplants prefer to stay in the shade or mild sunlight, marigolds will flourish in the blazing sun.
Therefore, I advise you to move your marigolds to a spot with plenty of sunlight—maybe a porch or an appropriately positioned window—if they’re not growing as much as they should.
You can also use a grow light if you live in a region where you don’t get enough sunlight. Learn about giving plants enough light to grow in my other article: How To Grow Flowers Without Sunlight (Ultimate Guide)
2. Ensure You Use Well-Draining Soil for the Marigold Plants
Plants need soil for support and nutrients, but not every kind of soil is suitable for your plant. Soil deficient in essential nutrients will result in poor plant growth just as much as soggy soil will. So, you must be careful when choosing suitable soil for your marigolds.
Marigolds prefer almost any well-draining soil—like sandy soil—but you might need to add peat moss to the soil before planting them. This material will help improve drainage and ensure you don’t end up with small or underdeveloped plants.
However, keep an eye out for the soil pH, as this can also affect the plants. Marigolds generally prefer neutral pH (between 6.0 and 7.0), and higher or lower numbers could lead to severe issues and affect the plant’s development.
I’d recommend you go easy on the fertilizer when keeping marigolds since they’ll flourish in leaner soil. If you must use fertilizer, opt for natural fertilizers or well-draining potting mixes.
Remember to use pots with drainage for your plants. These pots will ensure that water doesn’t collect at the bottom of the planter and affect plant growth.
3. Optimize Your Watering Practices
Every gardener knows watering is essential to growing beautiful plants—outdoors or indoors. However, you need to optimize the amount and quality of water you give your plants—just like with sunlight—to ensure the plants thrive.
Your marigold is most likely underwatered if it’s not growing tall. Fortunately, marigolds have somewhat tame needs when it comes to watering, unlike other plants. And you only need to water them once a week to ensure they flourish.
However, this frequency might vary if you live in a drier or wetter part of the globe. There are some signs to watch out for to confirm if underwatering is the reason for the marigolds’ stunted growth.
A telltale sign of underwatering is dry, faded, or wilted leaves and some parched marigold plants might also have curled leaves.
You should establish a consistent watering routine to fit the marigolds’ needs and use only clean water during the process. However, ensure you take care, so you don’t accidentally overwater the plant.
I recommend bottom-watering marigolds till excess water runs through the planter’s drainage holes. But you should only add more water after the soil is sufficiently dry.
Alternatively, you can use a moisture meter to keep track of the soil’s moisture content and establish a more efficient watering routine.
4. Control the Amount of Humidity Around the Marigold
Humidity and soil moisture content are closely related when keeping plants, and high or low humidity will affect your plants just as much as overwatering or underwatering. And while it’s necessary to keep the humidity of the plant’s growing environment at optimal levels, you must also ensure it’s constant.
Dry air can increase the transpiration rate and cause your plants to lose too much water in a short time. Additionally, high humidity can cause your marigolds to start drooping. To learn more about the causes of dropping marigolds, you can refer to my other article: Why Are Your Marigolds Drooping? 9 Causes and Fixes
So, I advise you to check the humidity levels in your home if you notice your well-watered plant is drying out.
Variations in humidity could stress the plant, resulting in faded leaves, root rot, underdeveloped plants, and an increased risk of disease. Of course, all of these could lead to shorter marigolds.
You should keep the humidity levels between 20% and 50% to ensure your marigolds flourish but take care to keep these levels as constant as possible.
A home humidifier is a great choice to regulate humidity since it’s easy to operate and quiet. But you might need to pair it with a high-grade hygrometer to ensure you keep track of the humidity levels.
Alternatively, you can mist the plants (if necessary) or use a humidifying tray.
However, these might not be necessary if you live in a relatively humid region. That said, I recommend you use the hygrometer to ensure optimal humidity all year.
5. Check That the Temperature Isn’t Too High
High temperatures can reduce metabolic activity in marigolds and affect their development. These plants are especially at risk of being affected by heat since they prefer full sunlight to thrive. Therefore, it’s necessary to check that the heat isn’t too high to affect the plant’s natural biological processes.
Marigolds generally prefer temperatures between 70oF and 90oF (21oC and 32oC), but they’ll thrive at higher temperatures if they get shade. However, growing your marigold plants at these temperatures would be best to improve their growth.
You can add some water to the soil if the temperature is too high or move the plant inside where it’s cooler. However, ensure you don’t overwater the plants in the process. Remember to establish a watering routine that’s consistent with these temperatures.
To monitor the plant’s temperature and avoid brown leaves, I advise you to keep a thermometer nearby.
Final Thoughts
Marigolds typically vary in size depending on species, planter size, and several other environmental factors. However, a plant that’s not growing tall might be a symptom of a problem with the marigold’s growing conditions. Fortunately, it’s pretty easy to fix the unlying cause, and you should end up with healthy plants afterward.
This guide is not an extensive list; you must take proper care of your marigold plants if you want them to grow tall.
