32 articles tagged "Soil Fertility and Fertilizers".

Figure 1. Initial symptom of blossom end rot on pepper.

In the past few weeks, we have received several reports about blossom end rot on tomatoes and peppers as the crops start to set fruit. Blossom end rot is a physiological disorder (not an infectious disease) that commonly occurs on tomatoes and peppers. Initial symptoms of the physiological disorder include dark green or brown water-soaked leisure occurring on the bottom of the fruit (Figure 1). The lesion then expands into sunken, leathery brown or black spots (Figure 2 and 3). In severe cases, the lesion can expand to half size of the fruit. The symptoms on tomatoes can be observed on fruit from fruit set to fruit the size of golf balls. Fruit on the same cluster tend to show symptoms simultaneously. On peppers, the symptoms are more likely appear during fruit expansion. The affected fruit often change color prematurely. Under moist conditions, opportunistic molds might develop on the affected tissues[Read More…]


Developing and mixing your nutrient solution is one of several very important steps in the production process. Mistakes are easily made when fertilizers are mixed. Not only does this have a cost implication, but also it can have severe consequences on production and therefore revenue. In the previous article Taking Care of Plant Nutrition in Your High Tunnel-Water Soluble Fertilizer Calculations, we have looked at basic calculations that is important when interpreting the fertilizer formulation in the bag and how to use that information to apply specific concentrations of mineral nutrients. In this issue, we will discuss what you need to consider when developing a nutrient program, and focus on key fertilizer characteristics and nutrient solution mixing tips. Developing a nutrient program A nutrient solution is just as good as the quality of the ingredients and the time spend on formulation, calculation and mixing. Fertilizer should be of a high[Read More…]


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Every grower will have to do some basic calculations when mixing a nutrient solution. Understanding some of the calculations will help you to apply the correct concentration of a nutrient or determine the concentrations of a combination of nutrients applied. In the previous article Taking Care of Plant Nutrition in Your High Tunnel-Water Hardness and the Removal of Unwanted Ions, we have discussed how to manage hard water, and unwanted high concentrations of sodium, chloride, iron, manganese and sulfur. Growers have different nutrient solution mixing and application options. Depending on the size of your high tunnel or greenhouse operation and the sophistication level of your nutrient solution application system, you might decide to use a single-bag mix (contains all needed elements), a two-bag mix (Tank A-calcium and iron, and half of potassium nitrate; Tank B-all other elements including phosphates and sulfates), or an individual element mix (individual compound fertilizers). The[Read More…]


It is essential, especially in hydroponics to start with a laboratory analysis of your source water. It is also important to do follow-up analysis throughout the year. Water quality can change especially where the water source is a well or a pond. In the article Taking Care of Plant Nutrition in Your High Tunnel-Water Alkalinity (Issue 627), we have discussed the importance of water alkalinity and how to correct high alkalinity levels. Additional elements of importance are Ca, Mg, S, Na, Cl, Fe and Mn. Knowing concentrations of these ions can help you to determine the need to purify water, leach or bleed more frequently, as well as to avoid these contaminants by choosing the appropriate fertilizer. Hard water might be generally associated with high alkalinity, but it is not always the case. Water hardness is a measure of the amount of dissolved calcium (Ca) and magnesium (Mg), expressed as if[Read More…]


In the past I have had many conversations with growers about plant nutrition in their high tunnels. A good plant nutrient management plan is an integral part of making a success of the crop you are growing. Plant nutrition is important to grow a strong and healthy seedling, the first step of a successful crop. Fertility management of especially vining crops (e.g. tomato, cucumber, peppers) are critical to achieving a good yield. It does not matter if you grow your crop in soil or in a soilless production system. Steering your crop to have the optimum balance between vegetative and reproductive growth will result in good yields over a longer period. It is important for growers to know what is in their water and soil. Therefore, soil analysis of a representative sample of the area that will be planted, and water analysis of a water sample from the source that[Read More…]


Figure 1. Take soil samples at 6 inches deep

We can never emphasize too much the importance of conducting soil tests. Ideally, soil test should be conducted on a yearly basis. The reason soil testing is so important is because it provides information about the nutrient composition of the soil so that growers will know how much fertilizer to apply for the following season. In addition, soil tests enables farmers to find out if there are concerns, such as pH, salinity etc. If these factors are off track, we might be able to address the problems before planting. In most cases, addressing the problems before planting is more efficient and cost effective than during the season. Purdue Agronomy Extension provides a list of laboratories that offer soil test services https://ag.purdue.edu/agry/extension/pages/soil_testing.aspx I will use the A&L Great Lakes Lab as an example, explaining how to use this service. A&L Great Lakes laboratories provide seven (S1 to S7) soil test packages.[Read More…]


Figure 2. Cowpea was worked into the soil

We have grown strawberries from Aug, 2015 to May, 2016 in one of our high tunnels at Southwest Purdue Agricultural Center. After taking the strawberry plants out of the high tunnel in the end of May, we did have enough time to grow a warm-season crop, like cucumbers. However, because for most of us June is such a busy time working in the field, we decided to put cover crops inside the high tunnel in the summer months and plant cool-season crops in the fall. Our primary goal of growing cover crops is to provide nitrogen for the following crops and increase soil organic matter. We decided to use a legume cover crop cowpea in this case because it has excellent drought and heat tolerance. Cowpea at a rate of 100 lbs per acre was sowed on June 17th. With the high temperatures inside the high tunnel, cowpea reached 30’’ high[Read More…]


We sometimes hear that excessive nitrogen could delay fruit set, stimulate excessive vine growth, and depress overall yield of pumpkins, but it is often unclear how much nitrogen is too much. This article reviews research on nitrogen fertilizer rates for pumpkins, and discusses the potential factors that might affect the recommended nitrogen rate. In a study conducted in 1987 and 1988 in Kilbourne, IL, four nitrogen rates were compared: 50, 100, 150 and 175 lb N/acre. The first three rates (50, 100 and 150 lb N/acre) were applied through fertigation, while the highest rate (175 lb N/acre)  was applied preplant and about a month after seeding. The study found the highest early and total marketable yields were obtained with fertigation of 100 lb N/acre. The lowest total yield was associated with the lowest nitrogen rate (50 lb N/acre). Fertigation with 150 lb N/acre and dry-blend with 175 lb N/acre delayed[Read More…]


In a recent visit to a high tunnel, we observed a severe salinity problem on tomatoes. Approximately one month after planting , most tomato plants in the affected area had not sent out any new leaves. Roots did not grow at all (Figure 1).  After conducting a soil test, very high soluble salt level explains these symptoms. This article reviews the basics of soil salinity. Salinity describes salt content in the soil. Virtually all fertilizer materials are salts, but they vary in their effects to increase salt concentration in soil solutions. In a field situation, precipitation in the form of rain and snow tend to leach salts.  Since high tunnels exclude rain and snow, elevated salt levels are a common concern for high tunnel vegetable growers. Table 1 are the salt indexes of common fertilizers. If you are using a premixed fertilizer such as 12-12-12, check the fertilizer components on[Read More…]


Census data showed that in 2014 Indiana (12 acres), Illinois (11 acres) and Kentucky (13 acres) dedicated a very small portion of their food crop acreage to production under protection. According to the USDA National Agriculture Statistical Service 2014 Horticulture Specialties Census, of all the states surrounding Indiana, Ohio and Michigan have grown and sold the most food crops under protection, 24 and 25 acres, respectively. The use of high tunnels for vegetable production seems to be a novelty in the Midwest. But it can be a very important tool for every vegetable grower as it can be used to modify the growing environment for crop earliness, to protect the growing crop against environmental stress, to reduce disease and insect pressure and to extend the growing season. Covering the soil with a high tunnel prevents natural rainfall from washing or leaching nutrients and soluble salts from the soil, can lead[Read More…]


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