Your quick reference guide for why your plants aren’t growing as quickly or as big as they should!
You’ve heard the phrase, “waiting for the grass to grow?” If your garden seems to be growing more slowly than grass, you might have a problem.
If your plants seem to be stagnant in terms of growth, there are a number of potential problems that could be at the root, and sometimes extremes on both ends will result in the same outcome — stunted plant growth.
Nutrient deficiencies, lighting and water issues, temperature fluctuations, climate and humidity, disease and pests, transplant shock, soil composition and pH, and plant spacing are all areas that drastically affect plant growth.
Keep reading for a list of the most common culprits that halt plant growth, as well as the corresponding solution. If you happen to catch the issue early, you can easily correct the situation and put your plants back on track.
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11 reasons your plants aren’t growing faster
If your plants – whether seedlings, transplants, or houseplants – seem to be struggling to grow, run through this list to find the root cause. If you find the culprit, it doesn’t hurt to consider the other potential issues as well – sometimes there are multiple factors at play.
1. Nutrient deficiencies
The most obvious reason plants struggle to get bigger is not having access to adequate nutrients. Brand-new seedlings don’t typically require additional fertilization other than a quality growing medium.
However, older seedlings and new transplants will struggle if they are starved of essential minerals (like NPK: nitrogen, phosphorus, and potassium). Calcium, magnesium, and sulfur are also important to healthy plant development, but the former three have the largest impact on plant growth.
Solution: First, bump up seedlings into bigger pots with new potting soil enriched with essential nutrients. According to the University of Maryland, you can start fertilizing seedlings as soon as they pop up, but the key is to use a water-soluble fertilizer.
The author writes to:
“keep soil evenly moist and fertilize with a balanced soluble fertilizer after seedlings emerge or after transplanting.”
https://extension.umd.edu/resource/stunted-growth-vegetable-seedlings
For established plants in the garden, start a regular feeding schedule every week, every other week, or once a month. Whichever regimen you decide on, dilute the fertilizer accordingly and keep a consistent schedule. Check out this article for ideas about which fertilizer to use.
2. Lighting issues
If you don’t think that a nutrient deficiency is cause for concern, then lighting issues may be to blame. All plants need light to engage in photosynthesis and produce food, but some plants need more light than others.
Flowering and fruiting plants need at least eight hours of sun a day, while leafy green vegetables can get by with much less. Read about lighting needs in this post in detail.
Not only does the amount of light matter, but the type of light as well. Plants need all the rays found in natural sunlight, so indoor-grown plants and seedlings require a full-spectrum bulb to mimic the sun’s natural rays.
Solution: Match your plants with their lighting needs. Dig up plants and transplant them to a sunnier location if need be.
Potted plants can easily be moved to follow the sun throughout the day. Supplement fruiting plants with a grow light to ensure that they’re receiving enough direct and indirect sunlight.
If your plants are getting too much sun, build a shade screen to protect cool-weather crops from the harsh midday light.
(You can learn more about shade cloth here).
3. Water issues
Another issue that can be either/or is watering. While it’s obviously ideal to give plants the exact amount of water needed, overwatering can be even more detrimental than underwatering.
Plants that don’t receive enough water will not grow as quickly as they would otherwise, but giving plants too much water encourages weak root systems that can’t support a mature plant. Plus, overwatering can lead to root rot and other fungal diseases that can be fatal for your plants.
Solution: Water plants only as needed. Check plant pots daily, scratching the surface of the soil and digging down an inch deep.
If you are met with moisture, let the plant dry out for another day. Most plants need about an inch of water a week, so water deeply and less often to encourage robust root development.
The best way to regulate watering is to install a drip irrigation system. (You can read more about irrigation here).
Sprinklers work well for some crops, but drip irrigation is better overall since the system uses less water and places moisture exactly where plants need it.
4. Temperature fluctuations
Plants are naturally slow to grow in colder temperatures — it’s part of the natural seasonal cycle. As a rule, most plants tend to grow more quickly as the weather warms and temperatures rise.
In the northern hemisphere, spring and summer are growing seasons, while in fall and winter plant growth will slow down and may even stop altogether. Drastic changes in temperature in early spring or late fall, may confuse plants and trigger them into a phase of either growth or dormancy at the wrong time.
Most growers start seeds indoors in early spring to get a jump-start on the growing season, but starting seeds much too early is a mistake.
Winter days are shorter than summer days, and it’s harder for seedlings to get the light that they need. They may actually grow too fast and become leggy with weak, spindly stems.
Even heat-loving plants have their limits when it comes to temperature. Although growth won’t happen at all in cold temperatures, at a certain point growth may slow and halt altogether as temperatures rise past a certain level.
Solution: Don’t start seeds too early, and don’t put plants outside too soon in the season. Make sure the temperatures line up with the crop before exposing your plants to cold weather.
Build a cold frame over your raised beds or plant in a hoop house to help mitigate colder temperatures by offering your plants some protection from the elements. Row cover is another excellent way to provide an extra layer of insulation, as much as 5 degrees!
Don’t forget to vent these structures on hot days — plastic is excellent at trapping heat, on both cold and hot days.
5. Climate and humidity
All plants are native somewhere, and we frequently grow plants outside of their ideal climates. Climate describes the weather patterns of certain regions and includes temperature, humidity, day length, and a number of other factors.
Plants will always do better in hardiness zones and areas that are closer to their climate of origin than those areas that aren’t.
Solution: Do your research on your hardiness zone (find it here) and keep your area’s climate in mind when purchasing plants and seeds for your garden.
If you do opt to grow tropical plants, keep them in a closed space like a greenhouse or indoor room where you can easily regulate temperature and replicate humidity with a humidifier.
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6. Disease
Any disease is sure to dampen plant growth if the disease doesn’t kill the plant altogether. Plants are susceptible to viruses and fungal infections, and once these infections take hold they can be difficult to get rid of.
Root rot is particularly troublesome and a common problem for many growers, especially beginning gardeners. Root rot develops if plants are left in waterlogged soil.
Damping off is another dreadful fungal disease that is particularly hard on seedlings. Damping off happens when seedlings are too moist and too warm, with very little airflow.
Solution: Run a fan in your seed-starting room or greenhouse to keep the air flowing and prevent the onset of some of these fungal diseases. Monitor your plants daily, checking the stems and leaves closely for anything unusual. Yellowing or crisping of leaves is one common indicator of disease.
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7. Pest pressure
Similar to disease, pest infestations can slow plant growth and potentially even cause death. Instead of putting energy towards growth, plants must turn their energy inward to fortify themselves against parasites and predators.
Solution: Be careful with new plants you introduce to your garden. It’s never a bad idea to isolate new plants for a few days to a week to monitor any signs of pests before tucking the new plant into your garden.
Incorporate a garden walk into your daily routine. Make sure to take time and check your plants for signs of pests like discolored or curling leaves and reside on plant leaves, and stems that could indicate the presence of tiny insects.
Know which bugs to look out for. If you do see insects or signs of pest damage, take these natural measures to control the pest invasion.
8. Transplant shock
Like humans, plants feel stress as a result of the environment around them. An excerpt from The University of Oregon’s ‘Botany Basics’ draws a connection between environmental stress and common plant problems:
“Either directly or indirectly, most plant problems are caused by environmental stress. In some cases, poor environmental conditions (e.g., too little water) damage a plant directly. In other cases, environmental stress weakens a plant and makes it more susceptible to disease or insect attack.“
https://extension.oregonstate.edu/gardening/techniques/environmental-factors-affecting-plant-growth
A common source of stress for plants is being moved into a new environment too quickly – in the gardening world, we call this transplant shock.
Solution: Always take the time to harden off seedlings before transplanting them outside. Over the course of a week, place any indoor or greenhouse-grown potted plants outside every day, and bring the plants inside at night. This process allows the plants to acclimate to outdoor conditions before anything is permanently planted in the ground.
If strong wind is stressing small seedlings, install a windscreen using T-posts and bamboo screens. If too much light is stressing cool-season plants, build an arbor over them or move the plants to a shadier location. If drought conditions are causing stress, install a drip irrigation system.
While pinching certain seedlings promotes more robust growth, over-pruning can trigger a stress response from plants. Be careful to never cut back a plant to more than a third of its original size, and don’t prune a plant hard before cold temps or persistently wet weather.
9. Soil pH
Not all soils are created equally. Check out this post for more information about the different types of soil.
Loam is universally best for most plants, although some plants can tolerate other types of soil. Soil pH also varies, with most fruits and annual vegetables preferring slightly acidic to neutral soil.
Be sure to do both a soil test and pH test periodically so so that you know the makeup of your garden and can plan accordingly.
Solution: Be sure to test the pH of your soil at the beginning of the season. Alkaline soils can be made more acidic with organic matter like compost, and acidic soils can be made more alkaline by the application of dolomitic lime.
It’s best to add any soil amendments prior to planting or at the end of the season after you pull your crops. If you need to adjust soil pH during the growing season, you can add compost to garden beds, but the effects may not be immediate. Over time the effects of building good soil will be much more noticeable.
10. Soil compaction
Not only is soil composition crucial to healthy plant growth, but so is the level of soil compaction. Plants that have to fight to grow roots through compacted soil won’t have as robust or efficient root systems as plants whose growing roots meet no resistance.
Solution: There is no quick fix for soil compaction, but minimizing driving and walking in compacted beds is a good place to start. Cut back on tilling, go no-till if possible, and strategically plant cover crops whose roots will break up compacted soil.
Add compost to compacted soil to improve the texture and drainage. For more information on combating soil compaction, read this article.
11. Plant spacing is too tight
Like most wild things, plants can only grow as big as the containers they are in. While it may seem like more plants equal bigger harvests, the reality is that plants that are too closely planted together will end up robbing one another of valuable space and nutrients. Give plants the space they need and they will be able to reach their full potential.
Solution: Thin seedlings before they get too big and begin to crowd out one another. Transplant plants into bigger containers as you notice their roots fusing together or growing out of the bottom of the pot.
Know how much space your mature plants will need and plant seedlings accordingly. If you have established plants that are already crowded, go through and dig out the plants too close together and transplant them to another location.
In summary
Stunted plant growth can be caused by a number of things, from nutrient deficiencies and watering issues to pest infestations, disease, and even too-tight spacing in the garden. Identifying the cause of your plants’ stunted growth is key to rectifying the situation and helping them get back on track.
Once you’ve found the cause, you can work to improve soil composition, provide the right climate and humidity, control pests and disease, and provide the right level of space for your plants to flourish.
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~Jonathon
Resources
“Environmental factors affecting plant growth | OSU Extension Service.” OSU Extension Service, 7 January 2008, https://extension.oregonstate.edu/gardening/techniques/environmental-factors-affecting-plant-growth. Accessed 19 January 2023.
“Stunted Growth of Vegetable Seedlings.” University of Maryland Extension, 20 July 2022, https://extension.umd.edu/resource/stunted-growth-vegetable-seedlings. Accessed 19 January 2023.
About the author:
When not writing content or growing flowers in her native Virginia, you can find Sarah hiking a long-distance trail deep in the woods. Follow along with Sarah’s adventures at http://sarahcolliecreative.com.
