Pepper Fertilizer Guide

By Julian Livsey, with contributions by Tony Ford
You have successfully germinated your seeds and you are looking at a batch of tiny seedlings. How do you now change those delicate little plants into the big and bushy capsicum plants, heavily laden with pods? The short answer is that you need to make sure the plants get their nutrients.

While it is possible to read a huge amount of information on how best to achieve the delicate balance of nutrients for optimum growth, it is well to remember that plants are phenomenally hardy and adaptable. Yes you can spend a lot of time on caring for your plants (and that's half the fun) but you will find your chile plants can get most of what they need even from poor soil, sunlight, water and air. You can grow perfectly good capsicum plants without the use of extra fertilizer, however, you can grow much bigger, healthier and more productive plants if you use fertilizer to give them the nutrients that they need. A word of caution though, it is easy to over fertilize and burn the roots, especially with younger plants.

My compost says it contains fertilizer, do I need to give them more?
Often the fertilizer present in compost only lasts a month or so before becoming depleted. This means that once your plants reach the stage where they are ready to bear fruit, there is no fertilizer remaining to give them that extra boost.

Nutrients
Let's talk more about nutrients. While there are quite a lot of major and minor nutrients essential for plant growth, ranging from Magnesium(Mg) to Zinc(Zn), the three main elements that are most often quoted are Nitrogen(N), Phosphorus(P) and Potassium(K) - referred to as the fertilizers' NPK value. Commercial fertilizer packaging often contains a set of numbers such as 5-5-5 or 10-8-8 . These numbers refer to the NPK balance.

NPK
Nitrogen helps boost a plant's foliage growth above ground. If your plants are lacking Nitrogen they may appear stunted. Leaves will pale, yellowing due to a slow down of chlorophyll production.

Phosphorus is required by a plant for the conversion of light energy to chemical energy during photosynthesis and also for cell communication and reproduction. It helps roots, fruit and flower development. If your plants are lacking Phosphorus they are likely to show signs of stunted or spindally growth, taking longer to mature. A chile deficient of Phosphorus will have difficulty taking all the other essential nutrients up through the roots.

Potassium regulates the water transfer through the plant, reducing water loss from the leaves, making them more resistant to cold and dry weather. Unfortunately deficiencies only become visible when they are severe. Older leaves may show as blotches or discolouration along the edges of the leaves, as well as a lack of flowering or fruit set.

Trace elements
As you can probably guess by the name, these elements only need to exist in very small quantities, yet they are still essential to plant growth. They include sulfur, calcium, magnesium, manganese, copper and iron and do jobs as diverse as helping the plant to fix nitrogen from the air to acting as a catalyst in chlorophyll production. A word of caution if you plan to add trace elements to your chile plants; while they are good for the plant in very small amounts, add too much and they become toxic.

pH
pH is a scale used to measure a acidity or alkalinity. The scale goes from 1 to 14 with a reading of 7 indicating a neutral balance, neither being acid nor alkaline. A plant's ability to take up nutrients is determined by pH and temperature. If your soil is too acid or too alcaline then the plant will struggle to extract what it needs. This in turn leads to deficiency symptoms.
pH chart

Types of fertilizer
There are numerous types available, and most will print the NPK balance somewhere on the label. The most common and popular fertilizers are the general purpose types which contain a balanced amount of Nitrogen, Phosphorous and Potassium. And the so called "tomato food" fertilizers which have a higher Phosphorus content, designed to help the plant along once you reach the flowering and fruiting stage. You can choose between powdered or liquid fertilizer, the latter allowing the nutrients to be taken up by the plant more quickly. And you can also buy fertilizer designed to boost trace elements.

Organic
Another question you may have is about organic fertilizer, specifically, is it an option for chile growing? The answer is yes, absolutely! As we get increasingly environmentally aware we may decide that we don't want to use manufactured chemicals to give our chile plants a boost. Organic fertilizers work in exactly the same way by giving the plant the nutrients it needs for strong and healthy growth. Organic nutrients typically tend to have lower NPK values than chemical nutrients. Coffee grounds for example would be approximately 2-0.3-0.6 Even with lower NPK values, organic fertilizers can easily contain enough to overfertilize so they should still be used with care!

The most common commercial organic fertilizers include blood, fish and bone meal which is a good balanced fertilizer. Fish meal is high in nitrogen and phosphorus. Seaweed is good for potassium and other trace elements. It is also worth noting that most organic fertilizers are expected to be "composted" (and ntherefore mostly decomposed) before being added to the soil. There is also a limit to the amount of "green manure" you can safely add to your soil, although nitrogen is not released until decomposition has taken place in any case. So, fancy making your own blend of organic fertilizer?

Alfalfa Hay: 2.45/05/2.1
Apple Fruit: 0.05/0.02/0.1
Apple Leaves: 1.0/0.15/0.4
Apple Pomace: 0.2/0.02/0.15
Apple skins(ash) : 0/3.0/11/74
Banana Residues (ash): 1.75/0.75/0.5
Barley (grain): 0/0/0.5
Barley (straw): 0/0/1.0
Basalt Rock: 0/0/1.5
Bat Guano: 5.0-8.0/4.0-5.0/1.0
Beans, garden(seed and hull): 0.25/0.08/03
Beet Wastes: 0.4/0.4/0.7-4.1
Blood meal: 15.0/0/0
Bone Black: 1.5/0/0
Bonemeal (raw): 3.3-4.1/21.0/0.2
Bonemeal (steamed): 1.6-2.5/21.0/0.2
Brewery Wastes (wet): 1.0/0.5/0.05
Buckwheat straw: 0/0/2.0
Cantaloupe Rinds (ash): 0/9.77/12.0
Castor pomace: 4.0-6.6/1.0-2.0/1.0-2.0
Cattail reeds and water lily stems: 2.0/0.8/3.4
Cattail Seed: 0.98/0.25/0.1
Cattle Manure (fresh): 0.29/0.25/0.1
Cherry Leaves: 0.6/0/0.7
Chicken Manure (fresh): 1.6/1.0-1.5/0.6-1.0
Clover: 2/0/0/0 (also contains calcium)
Cocoa Shell Dust: 1.0/1.5/1.7
Coffee Grounds: 2.0/0.36/0.67
Corn (grain): 1.65/0.65/0.4
Corn (green forage): 0.4/0.13/0.33
Corn cobs: 0/0/2.0
Corn Silage: 0.42/0/0
Cornstalks: 0.75/0/0.8
Cottonseed hulls (ash): 0/8.7/23.9
Cottonseed Meal: 7.0/2.0-3.0/1.8
Cotton Wastes (factory): 1.32/0.45/0.36
Cowpea Hay: 3.0/0/2.3
Cowpeas (green forage): 0.45/0.12/0.45
Cowpeas (seed): 3.1/1.0/1.2
Crabgrass (green): 0.66/0.19/0.71
Crabs (dried, ground): 10.0/0/0
Crabs (fresh): 5.0/3.6/0.2
Cucumber Skins (ash): 0/11.28/27.2
Dried Blood: 10.0-14.0/1.0-5.0/0
Duck Manure (fresh): 1.12/1.44/0.6
Eggs: 2.25/0.4/0.15
Eggshells: 1.19/0.38/0.14
Feathers: 15.3/0/0
Felt Wastes: 14.0/0/1.0
Field Beans (seed): 4.0/1.2/1.3
Feild Beans (shells): 1.7/0.3/1.3
Fish (dried, ground): 8.0/7.0/0
Fish Scraps (fresh): 6.5/3.75/0
Gluten Meal: 6.4/0/0
Granite Dust: 0/0/3.0-5.5
Grapefruit Skins (ash): 0/3.6/30.6
Grape Leaves: 0.45/0.1/0.4
Grape Pomace: 1.0/0.07/0.3
Grass (imature): 1.0/0/1.2
Greensand: 0/1.5/7.0
Hair: 14/0/0/0
Hoof and Horn Meal: 12.5/2.0/0
Horse Manure (fresh): 0.44/0.35/0.3
Incinerator Ash: 0.24/5.15/2.33
Jellyfish (dried): 4.6/0/0
Kentucky Bluegrass (green): 0.66/0.19/0.71
Kentucky Bluegrass (hay): 1.2/0.4/2.0
Leather Dust: 11.0/0/0
Lemon Culls: 0.15/0.06/0.26
Lemon Skins (ash): 06.33/1.0
Lobster Refuse: 4.5/3.5/0
Milk: 0.5/0.3/0.18
Millet Hay: 1.2/0/3.2
Molasses Residue: 0.7/0/5.32
Molasses Waste: 0/0/3.0-4.0
Mud (fresh water): 1.37/0.26/0.22
Mud (harbour): 0.99/0.77/0.05

 

Mud (salt): 0.4.0/0
Mussels: 1.0/0.12/0.13
Nutshells: 2.5/0/0
Oak Leaves: 0.8/0.35/0.2
Oats (grain): 2.0/0.8/0.6
Oats (green fodder): 0.49/0/0
Oat straw: 0/0/1.5
Olive Pomace: 1.15/0.78/1.3
Orange Culls: 0.2/0.13/0.21
Orange Skins: 0/3.0/27.0
Oyster Shells: 0.36/0/0
Peach Leaves: 0.9/0.15/0.6
Pea forage: 1.5-2.5/0/1.4
Peanuts (seed/kernals): 3.6/0.7/0.45
Peanut Shells: 3.6/0.15/0.5
Pea Pods (ash): 0/3.0/9.0
Pea (vines): 0.25/0/0.7
Pear Leaves: 0.7/0/0.4
Pigeon manure (fresh): 4.19/2.24/1.0
Pigweed (rough): 0.6/0.1/0
Pine Needles: 0.5/0.12/0.03
Potato Skins (ash): 0/5.18/27.5
Potaote Tubers: 0.35/0.15/2.5
Potatoe Vines (dried): 0.6/0.16/1.6
Prune Refuse: 0.18/0.07/0.31
Pumpkins (fresh): 0.16/0.07/0.26
Rabbitbrush (ash): 0/0/13.04
Rabbit Manure: 2.4/1.4/0.6
Ragweed: 0.76/0.26/0
Rapeseed meal: 0/1.0=2.0/1.0=3.0
Raspberry leaves: 1.45/0/0.6
Red clover hay: 2.1/0.6/2.1
Redrop Hay: 1.2/0.35/1.0
Rock and Mussel Deposits
From Ocean: 0.22/0.09/1.78
Roses (flowers): 0.3/0.1/0.4
Rye Straw: 0/0/1.0
Salt March Hay: 1.1/0.25/0.75
Sardine Scrap: 8.0/7.1/0
Seaweed (dried): 1.1-1.5/0.75/4.9
Seaweed (fresh): 0.2-0.4/0/0
Sheep and Goat Manure (fresh): 0.55/0.6/0.3
Shoddy and Felt: 8.0/0/0
Shrimp Heads (dried): 7.8/4.2/0
Shrimp Wastes: 2.9/10.0/0
Siftings From Oyster Shell Mounds: 0.36/10.38/0.09
Silk Mill Wastes: 8.0/1.14/1.0
Silkworm Cocoons:10.0/1.82/1.08
Sludge: 2.0/1.9/0.3
Sludge (activated): 5.0/2.5-4.0/0.6
Smokehouse/Firepit Ash:0/0/4.96
Sorghum Straw:0/0/1.0
Soybean Hay: 1.5-3.0/0/1.2-2.3
Starfish: 1.8/0.2/0.25
Sugar Wastes (raw): 2.0/8.0/0
Sweet Potatoes: 0.25/0.1/0.5
Swine Manure (fresh): 0.6/0.45/0.5
Tanbark Ash: 0/0.34/3.8
Tanbark Ash (spent): 0/1.75/2.0
Tankage: 3.0-11.0/2.0-5.0/0
Tea Grounds: 4.15/0.62/0.4
Timothy Hay: 1.2/0.55/1.4
Tobacco Leaves: 4.0/0.5/6.0
Tobacco Stems: 2.5-3.7/0.6-0.9/4.5-7.0
Tomato Fruit: 0.2/0.07/0.35
Tomatoe Leaves: 0.35/0.1/0.4
Tomatoe Stalks: 0.35/0.1/0.5
Tung Oil Pumace: 6.1/0/0
Vetch Hay: 2.8/0/2.3
Waste Silt: 9.5/0/0
Wheat Bran: 2.4/2.9/1.6
Wheat (grain): 2.0/0.85/0.5
Wheat Straw: 0.5/0.15/0.8
White Clover (Green): 0.5/0.2/0.3
Winter Rye Hay: 0/0/1.0
Wood Ash: 0/1.0-2.0/6.0-10.0
Wool Wastes: 3.5-6.0/2.0-4.0/1.0-3.5

Further reading
Plant Nutrition [external link]
Fertilizer [external link]
Nutrient Deficiencies [external link]
Nutrient Deficiencies Fact Sheet [external link]