10 Reasons Why Plants Don’t Grow
In this article, I share the Top 10 reasons why plants and trees fail to thrive.
First, let me briefly outline the reasons below before enlarging on each point. (For more information on each point, click on the jumplink provided.)
Here we’re talking about low nitrogen and seemingly lifeless soil. Soil preparation is critical before talking about soil ecosystems and microbial life, and how they work to support healthy plants.
This might sound obvious but a good understanding of what every plant needs and watering them accordingly is crucial.
Plants stress and die in heat. Mulching offers many benefits, including retaining moisture in the soil on very hot days.
It’s not difficult to either fertilise too much or starve plants to death. The rule of thumb, “little and often” applies to fertilising most plants.
When transplanting, we should try to avoid transplanting shock as this uses the energy from the plant, giving it a poor start. The use of humectants prior to planting often avoids transplanting shock, allowing plants to grow instead of recovering from shock.
It goes without saying, planting out of season very often produces poor outcomes.
Exposing a plant to too much sun or too little is an obvious error made too often. A less obvious error is planting two incompatible plants next to each other. For example, beans and chilli capsicum are a no go. In another example, planting a raspberry next to a strawberry can cause a wilting disease.
All plants and trees have a specific PH requirement. Failing to respect this often has dire consequences.
This is the cause of a lot of early seedling loss.
Weeds represent competition to our plants and sometimes give off chemicals that our plants don’t like.
1. IMPOVERISHED SOIL
Soil is not a lifeless medium but rather an abundance of organisms and soil life that all play a part in the health of the biosphere and will determine whether life is sustained or not.
So, how do we turn lifeless soil low in nutrient and organisms into a fertile garden flourishing with growth?
While there are many ways to do this, here is one simple organic approach.
Clear the area of weed growth and spread a thick layer of mulch. This can be straw, pea straw or another type. Sprinkle a few good handfuls of chicken or cow manure over the straw and water in the straw and manure.
Note: Cow manure from a dairy has a lot of nutrients that microbes love.
Keep watering the straw regularly to ensure good soil moisture is retained.
Water into the straw liquid humate every 6 weeks at the recommended rate.
At about Week 6, the soil should be moist and able to be turned over once. First, add some good organic complete fertiliser (GROlife is my favourite) grow-life). Then turn the soil up over and on top of the mulch that is now starting to break down. Don’t be tempted to chop the soil into fine particles; rather, just turn it on to itself, then spread a layer of mulch over what you have turned over and water in again.
After Week 6, plant your first crop. This will be a sacrificial crop to use as a green manure. You can plant this crop thick, as you will not be growing it to maturity. A mixture is good too. Legumes are particularly good as they fix nitrogen to the soil and are great soil builders.
Peas and beans are a good start and can be sourced from a grain and fodder store at a reasonable price. Other things that can be grown are ryegrass, buck wheat, clovers, Lucerne (alfalfa) and mustard seed to name a few.
Once the green crop has been turned into the ground, all that you need to give your garden is that most valuable ingredient in life: time. About two weeks will usually do the trick.
2. LACK OF WATER OR TOO MUCH WATER
It is all about balance, regularity of watering and understanding your plant’s watering requirements, and how they grow.
For example, Tomatoes need little watering when they are young. When they are growing, they like to be flooded then allowed to dry out until they start to wilt a bit. This causes them to sink deep roots into the soil and become strong plants.
However, when they start to set fruit, they require more regular watering to fill the fruit.
Leafy vegetables grow foliage and mature quickly and will do better if they receive more regular watering.
Some plants tolerate overhead watering; plants like tomatoes cucumbers or pumpkins prefer ground watering.
Plants in pots will require more regular watering and mulch to keep them cooler in summer preventing some evaporation and temperature fluctuations.
Mulching will save lots of water and keep soil alive.
3. SOIL TOO HOT
When soil becomes very hot and water retention is poor, the plants become stressed and their energy goes into staying alive rather that growing larger.
If the plants don’t die, they can bolt to seed quickly in a last-ditch effort to reproduce themselves or become bitter or tough.
Other bad things happen in the soil too. Worms go deeper into the soil to find moisture, taking their valuable nutrition source away from your plant. Microbes and healthy soil fungi die. These life forms are vital for decontaminating the soil; they also contribute to the uptake of food to your plant and they kill off the enemies to your plants. So when they die, the microbial population numbers start to decrease rapidly leaving the soil without life support.
What are some of the causes of the soil overheating?
- Overusing the old herbicides (kills off the biosphere).
- Turning the soil over.
- Lack of mulching.
- Lack of watering: not keeping the soil moisture constant.
4. OVER FERTILISING
Isn’t it always the way? We are either too heavy handed and burn them to death, or starve the poor plants to death.
General rule of thumb: little but often should apply most of the time.
Get to know your plants and feed them according to how they grow and what they produce. For instance, a rose or citrus tree flower a lot and thereby use up a lot of nutrient in doing so. Therefore, potassium and fruit promoting elements, like magnesium, are necessary to support this production of fruiting.
Fruit trees should be fed right after fruiting after they’ve expended lots of their energy. At this point, they are hungry for nutrients. Also, feed them in spring to promote new leaf and bud development, and in autumn to store energy into the root system.
Nitrogen that causes rapid greening up in plants can be too hot for plant root systems. It can produce excessive soft growth and will also burn out quickly if not used in a complete balanced fertiliser.
Organic fertilisers are generally safer to use, and provide better plant available nutrients.This will equate to healthier vegetables. For example, commercially grown spinach renowned for its iron content was found to only have about 9% of the iron it was supposed to contain. Why? Because it was commercially grown in nutrient depleted soil. Some fertilisers are specific to the PH of the plant. It’s important to find out this information before fertilising.
5. TRANSPLANTING SHOCK
Imagine two scenarios…
You buy a punnet of beautiful tomatoes and have prepared your ground ready for the big day. You take them out of the tray, carefully plant them into the ground and water them.
You return in ½ hour to find them wilting and not looking so good. What went wrong?
The tomatoes stressed out because of the shock they sustained at the point of transplanting.
And the big problem is this shock uses up plant energy. Instead of the plant taking off and growing from day one, it is in recovery for the next few days.
Scenario 2: The Solution
You buy a punnet of beautiful tomatoes and have prepared your ground ready for the big day. You take your tomatoes to a tray you have prepared with some Seasol solution and you place your punnets into the tray so they can soak up the solution in the tray.
That afternoon, after a few hours in the tray of solution, you plant them out.
You return an hour later. Your plants are upright and look healthy and strong and they start growing from Day 1.
6. WRONG SEASON TO PLANT
As with all plants, there is an ideal time to plant and a bad time to plant.
Citrus are best planted in September when the ground is warming up
Stone fruit is best planted in its deciduous state bare rooted, as with roses, quite often in winter.
Vegetables should be planted in their recommended seasons to be the most successful.
Out of season planting could mean plants go straight to seed or do not have enough time to fruit. Germination may also be frustrated by soil that is too cold.
Keep a planting calendar and make note on any anomalies that are not supported by your planting guide.
Where I am in the Hills, it is quite different to down in Golden Grove, for instance. Our season starts about a month later and last a bit longer. The chill zone is also quite different. The point is, every area is a unique and needs to be tested and trialled for crop success.
It is a good idea to record what happens for future years.
7. WRONG PLACE TO PLANT
Plant labels usually give you a good guide to position of planting, for example, full sun, part shade or shady position. This can be an important guide worth looking at before you buy your plants.
When you have bought them, a great idea is to place them where you intend planting them while they are still in their pots. Remember to keep them watered. This will allow you to see if they are able to tolerate the spot. If they start stressing out, you can move them under shade to recover. This will also allow you to gradually harden them up, a few hours at a time if required.
The four positions we need to be aware of in particularly are:
- Windy areas, which can burn or damage plants
- Areas in full sun, which can burn the plant or dry out the ground around the plant
- Very dark areas, where only specific types of plants will grow
- Reflective heat will burn your plant quickly, such as plants positioned against hot fences
A less obvious error is planting two incompatible plants next to each other, or what we might call wrong neighbours.
The wrong neighbour relates to bad companion planting, particularly when planting up a tight planter box, and plants are very close to each other.
Yes, some plants grow well together while others don’t. For example, beans and capsicums don’t grow well together but beans grow well with radishes and peas. Strawberries can give raspberries a wilt disease if grown next to each other.
Some plants grown with each other aid the health of the plants by cleansing the soil or keeping pests away from crops. We can and should study this further in the next blog.
8. WRONG PH IN THE SOIL
The PH scale is a measure of soil acidity or alkalinity.
7 is about neutral. 1 is highly acidic while 14 highly alkaline.
Every plant has its ideal PH range and when it is in this range, subject to soil health of course, plant nutrient is readily available.
This is critical when growing acid loving plants like Camellias, azalais, blueberries, cranberries or even raspberries. When the soil is not acidic enough, plants can’t get enough nutrient and quite often turn yellow and die. Fruit grown on the wrong PH will be tasteless.
PH should be corrected weeks prior to planting so corrective amendments have time to activate in the soil, such as sulphur.
9. PLANTS ATTACKED BY PESTS
The three golden rules to pest and disease management are observe, observe, observe.
One of the best times to find insects eating our young plants is at night, that is why good gardeners take the time to go out an investigate the nocturnal creatures that do the damage.
Another way to observe is to see how the pest attacks the plant, as this will give us a better idea of what is eating or sucking it. For instance, a chewing insect will leave bite marks while a sucking insect will leave a honey dew secretion, which is sticky on the leaf.
Some seasonal preventative measures may be required to defend the plants from infestation by deterring insects, like tomato dust. Or a clay spray on citrus to stop the gall wasp from laying her eggs. Eco oil is another clean-to-use deterrent for citrus leaf miner and other chewing and sucking pests. By cloaking the plant with oil, we set up a barrier to bad insects but don’t hurt good predatory insects, such as ladybugs, lace wings and other Beneficials.
General observation of plants will usually tell us something is not right. For example, plants may wilt or lose colour when they are being attacked.
Soil borne problems such as excessive nematode populations can be controlled by certain types of plants like green manure crops, marigold flowers or Lucerne mulch. Crop rotation is also a good way to keep nematode levels balanced. There are good and bad nematodes, and the good ones convert nitrogen in the soil making it available to our plants.
10. PLANTS CHOKED BY WEEDS
How is it that weeds always grow better than my plants?
That’s a question frequently asked.
Weeds not only compete for the nutrients in are soil, but they choke out our plants and some weeds have chemical that are not good for our plants.
Cultivation of weeds is the preferred option to minimise the use of chemicals that have a detrimental effect on soil organisms.
Often if weeds are hoed into the ground and mulched over they can be controlled easy, and provide a mulch. For example, soursobs are a very nutritious mulch as they are quite high in nitrogen and have a high-water content making them break down quickly.
If you see a weed seeding off and don’t have time to weed, at the very least, snap off the seed head. This will prevent it from seeding off. Remember, there are many seeds in that seed head.
David is the owner of Allingtons Lawn & Garden Care. He has been in the horticultural industry for nearly two decades, and has pioneered an exciting gardening services business at the cutting edge of the industry. Through this site, he shares his knowledge and expertise. Return to the home page to view all on offer or drop us a line via the contact form.