Helping Garden Beans With Yellow Leaves – What Causes Yellow Leaves On Beans

by johnah on November 3, 2020

What Causes Yellow Leaves On Green Beans?

The most common cause of yellowing leaves on green beans is a lack of calcium in the soil. Calcium helps maintain healthy leaf surfaces and prevents them from cracking or breaking off. Too much calcium in the soil can result in too much acidity which results in stunted growth. Too little calcium in the soil can lead to a buildup of carbon dioxide (CO2) which causes the plant to not have enough oxygen. Too much CO2 in the soil can cause root rot.

Causes Of Low Nitrogen Levels In Soil:

1. Excessive fertilizer application: Over fertilization with nitrogen can result in low levels of nitrogen in the soil.

If your garden is over fussed with with fertilizing, then it may be best to reduce the amount of fertilizer applied to avoid any problems like low levels of nutrients in the soil.

2. The age of your soil: Another cause for low nitrogen levels in the soil may be due to the age of the soil you’re using.

Any organic matter that was present in the soil before is long gone and has already been exhausted by previous crops. Over time nutrients are taken from the soil by other organisms or washed away by rainfall. The only option if you’re looking to fix low nitrogen levels in your soil is to add fertilizer.

3. Climate: Low nitrogen levels in soil are common if you live in a very wet climate, since rainfall washes away nitrogen.

What is Nitrogen Deficiency?

Nitrogen deficiency in plants can be recognized by several yellowing of the leaves on your plant; the older leaves are more likely to exhibit symptoms of nitrogen deficiency than the younger leaves. Specifically, the veins of the leaf will turn a dark green to black color. The edges of the leaves may also curl up slightly. Soil nitrogen deficiency can frequently occur in container-grown plants if: 1) You are using a soil that has no nutrient value or neutral pH (many prepared potting soils fall in this category), 2) You are over-fertilizing with nitrogen, or 3) You are not feeding your plant enough.

How to Treat Nitrogen Deficiency in Plants:

If you notice your plant is suffering from nitrogen deficiency, there are several methods you can use to treat the problem. The first thing you should do is stop fertilizing your plant with a water-soluble nitrogen fertilizer, as this will just make the problem worse. Instead, you want to feed your plants with a high-analysis nitrogen fertilizer such as 16-4-8.

If you have access to bat guano, this is an excellent choice.

Don’t overdo it with the nitrogen, though. Remember, too much of anything is bad! You can also add a small amount of phosphorus along with the nitrogen if your plant needs it.

Mix the fertilizer at half strength when applying it to your plants, and do this weekly for four to six weeks. If you are growing in a container, it’s best to transplant your plant into a larger pot if possible.

Deficiency and Toxicity of Magnesium:

Magnesium is an essential element for cellular metabolism, especially for photosynthesis. Most plants need it. Nitrogen and sulfur can tie up magnesium, so high levels of these elements may contribute to magnesium deficiency in some plants, including Cannabis.

If the plant is getting enough light, magnesium deficiency can cause leaves to have a yellow hue. The older lower leaves are most commonly affected. Yellowing can occur throughout the entire plant if there is not enough water or the plant is lackadaisical.

Magnesium Deficiency Symptoms:

1. High Nutrient Levels: If nutrients such as nitrogen and sulfur are at healthy levels but the pH of the soil is too high, this may contribute to magnesium deficiency in some plants.

2. Cool Temperatures: Magnesium is essential for plants to process carbohydrates and thrive when temperatures are between 60 and 80 degrees Fahrenheit.

3. Lack of Water: If the plant is not watered enough, it will not be able to take up enough magnesium through its roots.

4. Poor Soil: Magnesium gets locked in soil that has a high pH level and low levels of organic material.

5. Salt Build-Up: Magnesium is one of the most affected minerals by salt build-up in the soil.

6. Sunlight: Magnesium helps a plant process light, so if the plant does not receive enough sun, it will suffer from a magnesium deficiency.

Helping Garden Beans With Yellow Leaves – What Causes Yellow Leaves On Beans -

Magnesium Deficiency Treatment:

Since magnesium is involved with nitrogen metabolism in plants, adding more nitrogen compounds will cause more magnesium to be taken up by the plant. If the magnesium level is low, applying finely ground up eggshell to the soil around the plant helps increase magnesium levels in plants, as does applying gypsum or ground-up limestone to the soil. You can also apply wood ash or bone meal, but avoid using too much unless you know exactly how much phosphorus is in each.

Magnesium deficiency is often confused with zinc and copper deficiencies. Use the tips listed for combating those issues as well if you think your plant has a magnesium deficiency.

When growing Cannabis, magnesium deficiencies are most commonly found in hydroponic setups where the pH levels of the water are incorrect.

A lower root environment that contains plenty of oxygen helps the roots take up magnesium more effectively.

The addition of more compost and humus can also help if you are growing in soil since humus contains magnesium.

If magnesium levels are very low in the soil, it may be necessary to replace it with sand that contains a higher level of minerals. Always make sure to test the pH level of the new soil before using it.

Since magnesium plays a role in nitrogen metabolism in plants, adding more nitrogen-rich compounds will cause the plant to take up more magnesium. Compost, leaf mold, and well-rotted manure all contain high levels of magnesium.

Magnesium trisilicate is an organic form of magnesium that increases the water retention capabilities of soil. It also protects plants against temperature fluctuations.

Magnesium chelate is an organic chelated form of magnesium that helps increase a plant’s uptake of magnesium and is easy for the roots to absorb.

Chelated magnesium is an inorganic form of magnesium that is highly water-soluble and accessible to plant roots.

Helping Garden Beans With Yellow Leaves – What Causes Yellow Leaves On Beans - Picture

Magnesium sulfate is an inorganic salt that is often used as a fertilizer due to its high magnesium content. It can also be used to increase the water retention capabilities of soil.


Calcium is an important element for plant cell walls, making them rigid. Calcium also aids in nutrient transport and helps plants take up nutrients such as nitrogen.

Calcium is essential for plants to grow, but most soils have a calcium to phosphorus ratio that is not in the best interest of the plants.

Most healthy plants have a need for more calcium than phosphorus, and Cannabis is no exception. Marijuana roots rarely take up enough calcium, making calcium deficiency common.

Most tap waters have plenty of calcium, especially if it is derived from limestone. Hard water contains elevated levels of calcium.

If you are growing indoors, be sure to use either bottled water or water that has been through a reverse-osmosis filtration system so the calcium content is higher than normal.

Calcium nitrate is an inorganic salt that contains both calcium and nitrogen. It can be used as a fertilizer to increase the level of calcium within the soil.

Gypsum is an inorganic salt that contains calcium and sulfur. It can be used as a soil amendment to adjust the calcium to phosphorus ratio.

Dolomite is an inorganic soil amendment that contains both calcium and magnesium. It is often used to increase the calcium levels in soil.


Cobalt is an element that plays a role in photosynthesis. It is found in many nutrients and fertilizers that help promote plant growth.

COB (Coated Oxygen Bulbs) provide a more complete light source for your plants. The coating on the bulbs releases O2 and increases the efficiency of the Sodium Bulbs.

Helping Garden Beans With Yellow Leaves – What Causes Yellow Leaves On Beans |

Cobalt plays an essential role in the creation of chlorophyll, which allows the plant to perform photosynthesis. Without Cobalt, the plant cannot produce it’s food and will slowly waste away even if other nutrients are provided.

Most tap water contains elevated levels of cobalt.

Cobalt Chloride is an inorganic salt that can be used as a fertilizer to ensure that the plant has an adequate supply of cobalt.


Nickel is an element that plays a role in photosynthesis and is vital to the health of your plant.

Nickel plays a role in photosynthesis, but not a large one. In fact, if your plant does not get enough sunlight, supplementing with nickel will not increase the yield or potency significantly.

Most tap water contains an adequate amount of nickel.

Nickel Sulphate is an inorganic salt that can be used as a fertilizer to ensure that the plant has an adequate supply of nickel.


Zinc plays a role in photosynthesis and overall health, but it is not absorbed well through the roots and tends to be toxic in large amounts.

Helping Garden Beans With Yellow Leaves – What Causes Yellow Leaves On Beans - Image

Zinc is an essential nutrient for plants, but it is not taken up directly through the roots. For zinc to be taken up by the plant, it must be converted from it’s ionic form to a molecular one by either a fungus or a bacteria that lives on the roots of the plant.

Zinc Fingers are synthetic organisms created by humans to provide a source of bio-available zinc to plants in a non-toxic form.

The process of creating Zinc Fingers is quite complicated and expensive, but will probably become more affordable in time.

Zinc Fingers are living organisms and need to be taken care of. They provide an endless supply of zinc for your plant, but will need to be replaced every one to two months.

You have decided to use Zinc Fingers for your plant’s nutrition. You place them in the cups with the seeds and pour water into each cup until it reaches just below the bottom of the finger.

You place the cups in a warm, sunny location and wait. Within 24 hours you will see the first signs of growth.

Days turn to weeks as your plants grow larger and larger. You provide it with water and nutrient rich fertilizer and it responds well to your care…

Except it isn’t. Your seeds never sprouted. You check and re-check but there is nothing there, not even a seed.

It’s been almost two months since you started this project and you’ve failed. You’ll need to think of something else if you wish to make money from the farm.


Sources & references used in this article:

Occurrence of bean yellow mosaic virus in subterranean clover pastures and perennial native legumes by SJ McKirdy, BA Coutts, RAC Jones – Australian Journal of Agricultural …, 1994 – CSIRO

Identification of a pathogenicity island, which contains genes for virulence and avirulence, on a large native plasmid in the bean pathogen Pseudomonas syringae … by RW Jackson, E Athanassopoulos… – Proceedings of the …, 1999 – National Acad Sciences

Bean disease and pest identification and management by RA Buruchara, C Mukaruziga, KO Ampofo – 2010 –

A monographic study of bean diseases and methods for their control by WJ Zaumeyer, HR Thomas – 1957 –

Breeding common bean for resistance to diseases: a review by SP Singh, HF Schwartz – Crop Science, 2010 – Wiley Online Library

The relationship of certain legume mosaics to bean by WJ Zaumeyer, BL Wade – J. agric. Res, 1935 –

Yellow mosaic of Mung (Phaseolus aureus L.). by TK Nariani – Indian Phytopathology, 1960 –

Bacterial wilt of Beans (Bacterium flaccum-faciens Hedges), including comparisons with Bacterium phaseoli. by F Hedges – Phytopathology, 1926 –

Manganese toxicity in field and market garden grops by MP Löhnis – Plant and Soil, 1951 – Springer



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