when to apply fertilizer to vegetable garden

Ep. 14 – Top 10 Simple Tips for When to Apply Fertilizer to Vegetable Garden

Get the scoop on when to apply fertilizer to vegetable garden this growing season as well as get a basic understanding of how to use fertilizer to grow a bountiful harvest. 

If you’re anything like me when I first started growing my own vegetables, the idea of properly fertilizing the soil was intimidating. There are so many different types of fertilizers out there – which one do you use? When do you apply it? How much is enough but not too much? It’s pretty confusing! Plus fertilizers can be expensive, so you want to know you are spending your money effectively! So, in this episode, I’m going share the basics of fertilizing your vegetable garden so you can give your plants the nutrients they need to thrive. 

We’ll walk through several tips for deciding when to apply fertilizer to the vegetable garden and by the end, you’ll feel confident applying fertilizer like a pro.

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Hey guys, and welcome to episode 14 of the podcast! Today we are discussing fertilizing our gardens as I share 10 tips for deciding when to apply fertilizer to vegetable garden as well as how to decide what to add. 

But before we dive into those tips. Let’s go over a few key terms and ideas about fertilizer and lets start with a definition so what is fertilizer?

Fertilizer serves as the nourishment for our vegetable garden, enriching the soil with essential nutrients required for plant growth. It provides an immediate nutrient boost to address any deficiencies that plants may face. Fertilization plays a pivotal role in garden care, ensuring abundant harvests. A fertile soil base is fundamental for healthy plant development, with fertilizer creating a nutrient-rich environment to support growth. Soil nutrients fall into two main categories: Macro Nutrients and Micronutrients, each vital for various stages of plant growth.

Macronutrients include:

  • Nitrogen
  • Potassium
  • Phosphorus
  • Calcium
  • Magnesium
  • Sulfur

Micronutrients include:

  • Boron
  • Zinc
  • Manganese
  • Iron
  • Copper
  • Molybdenum
  • Chlorine
  • Nickel

When we think about fertilizers we are often only considering the macronutrients, but without the availability of micronutrients to our plants they can not thrive! 

Top 10 tips for When to apply fertilizer to vegetable garden

Applying fertilizer to your garden does not have to be difficult, in fact if you make just a few simple decisions early on in your garden season as well as some general guidelines, you can create a fertilizer schedule that can keep your garden healthy all season long! Here are my top tips for when to apply fertilizer to vegetable garden to give you a good start towards properly fertilizing your garden. 

Tip #1: Test your soil

Before we dive into when to apply fertilizer to your vegetable garden we need to understand our soil and know what fertilization your soil needs. This can be accomplished by conducting a soil test. 

Soil testing measures the nutrient availability in the soil. This information helps determine the availability of nutrients for plants and the recommended amount of fertilizer. Additionally, soil tests assess soil pH, organic matter, and exchangeable acidity, providing insights into the need for lime application and the appropriate dosage.

With the soil test results you can readily amend your soil (fertilizer, organic matter content, etc) prior to planting so that your soil is healthy and ready for the growing season. 

You can use an at home soil test for a quick evaluation of your soil or you can send a soil sample to your local extension office to be tested. These offices are often a wealth of information and resources for growing in your local area.

Also Read: Soil vs Dirt: Know the Difference to Prepare your Garden

Tip #2: Understanding NPK values 

The next tip is another thing we should be clear on before we decide when to add fertlizer, and that is understanding the NPK values of fertilizers. Often, the first thing you will notice when purchasing fertilizer is that most are labeled with a 3 number ratio. it will look like 1 – 1 – 1, 3 – 2 – 1, etc. This is the NPK ratio and describes the relative percentages of each of the primary macronutrients.

The first number represents nitrogen. Fertilizers with a high levels of nitrogen, like blood meal will help improve leafy green growth in your plants. The second number represents the amount of Phosphorus. Fertilizers high in phosphorus, like bone meal can help improve flower, fruit production and root development. The last number represents Potassium which is beneficial for general plant and cell metabolism. 

Often times the best fertilizer is a balanced fertilizer which will have equal numbers of each of these macronutrients as well as many of the micronutrients. Very few fertilizers can be considered a single nutrient fertilizer, but you may find that in order to get the right mix of all nutrients for your garden you’ll have to use a few different types of fertilizers.

Tip #3: Applying Fertilizer Based on Crop Needs

When determining the optimal timing for fertilizer application, various factors come into play! One crucial aspect to consider is the feeding requirements specific to the types of vegetables being grown in your garden. 

Garden crops can be categorized into three primary groups based on their nutritional needs. These categories are heavy feeders, moderate feeders, and light feeders, each demanding varying levels of nutrients. 

Heavy feeders, which encompass highly productive plants, benefit from both a pre-planting fertilization and a mid-season application of slow-release and liquid fertilizers on a weekly basis. Examples include Brassicas (cabbage, broccoli, brussels sprouts), cucurbit crops (cucumbers, melons, squash), corn, eggplant, onion, tomatoes, and peppers. 

Moderate feeders, such as root vegetables like beets, carrots, okra, potatoes, and sweet potatoes, can gain from organic matter and mulch before planting. 

On the other hand, light feeders like bush beans, mustard greens, peas, southern peas, and turnips require initial feedings but often do not necessitate additional nutrition. It’s essential to tailor the fertilization approach to the specific needs of each type of crop for optimal growth and yield.

It can be beneficial to plant crops with mixed fertilizer requirements in the same bed as to avoid depleting nutrients too quickly! This is also why it is not advised to plant brassicas and nightshades in the same bed as both are heavy feeders!

Tip #4: Applying Fertilizer based on stage of Growth

When it comes to the best timing for fertilizing your plants, consider their specific growth stage. This not only helps in choosing the right type and amount of fertilizer but also prevents over or under-fertilization, ensuring your plants’ well-being. Here are some key guidelines for different growth phases:

  1. Seedlings: Supporting the early growth of seedlings effectively involves using half-strength liquid fertilizer weekly.
  2. Transplants: For best results with transplants, it’s advisable to opt for full-strength fertilizer on well-watered soil. Additionally, consider using an organic root-stimulating fertilizer like Organic Rev to minimize transplant shock and encourage healthy root development.
  3. Mature/Fruiting Vegetable Plants: To enhance overall growth and productivity of mature or fruiting plants, incorporate a slow-release granular fertilizer every 3-4 weeks and supplement with liquid fertilizers weekly.

By matching nutrient input with your plants’ growth stage, you can foster robust and thriving plant development. Make sure to follow the provided fertilizer applications instructions closely to determine the precise amount needed for each plant, ensuring optimal care and growth results.

Tip #5: Set frequency based on Methods of fertilization

The timing of fertilizer application depends on the method you choose! There are three main methods: pre-planting, side dressing, and foliar feeding.

Pre-planting Fertilizer:

Before planting your crops, ensure the soil is rich in nutrients by using granular fertilizer and organic materials like compost. Blend the fertilizer well with the soil and then sow your vegetables!

Side Dressing:

For side dressing, apply the fertilizer around the base of your vegetable plants. If using granular fertilizers, mix it thoroughly into the soil around the root zone.

Foliar Feeding:

Foliar feeding involves spraying liquid fertilizer directly onto the leaves of your plants. This method can provide direct nutrition to stressed, sick, or weak plants. It complements side dressing and is beneficial for plants in need. It is often done more often.

*Note: Organic garden fertilizers are usually safe for foliar spraying but be sure to check the labels

Tip #6: Organic vs. Synthetic Fertilizer

Another distinction that helps you determine when and how often to apply fertilizer is whether a fertilizer is an organic fertilizer or a synthetic inorganic fertilizer. If you are an organic gardener, you may want to use worm castings, compost tea or other organic fertilizers like kelp or fish emulsion. These types of fertilizers contain a variety of micronutrients and will typically break down slowly in the soil so that they can be absorbed by plants over time.

Inorganic fertilizers, on the other hand, tend to provide an immediate boost of nutrients and are generally manufactured products. But because it is a fertilizer that is not in its natural form, it can often be more potent and lead to over-fertilization if not applied correctly.

In general, organic fertilizers are better for long-term soil health and sustainability, while synthetic fertilizers may provide a quick fix but can harm soil quality in the long run. Consider the specific needs of your garden and plants when choosing between organic and synthetic.

Tip #7: Granular vs liquid

Now let’s talk about granular fertilizers vs liquid fertilizers. I have mentioned both throughout the episode, but I want to take a moment to give a little more detail and context on these fertilizer types.  Granular fertilizers are often slow-release, meaning they break down gradually in the soil and provide nutrients over a longer period. They are typically applied to the soil surface before planting or during early growth stages. On the other hand, liquid fertilizers are fast-acting and quickly absorbed by plants through their leaves or roots. They can be used as a foliar spray or added to water for regular irrigation.

When it comes to frequency, granular fertilizers are typically applied less frequently than liquid plant food since they provide plant nutrients over a longer period. However, the frequency may vary depending on the specific product and crop needs. It’s always a good rule of thumb to read and follow the instructions for your chosen fertilizer carefully.

Tip #8: Slow Release Vs Fast Release

Another thing to consider when applying fertilizer is whether a particular fertilizer is quick-release vs. slow-release. As mentioned earlier, quick-release fertilizers are liquid for immediate plant nutrient boost. Slow-release granular fertilizers release nutrients gradually over time, ideal for seasonal soil amendments.

Tip #9: Fertilizing based on rain forecast? 

One common question asked is can I apply fertilizer before or after heavy rains. As a general rule, fertilizing around heavy rain is ill-advised! Instead fertilize when you are expecting at least 2 rain free days or only light rain. 

Additionally, during the heavy rains of early spring, you may need to apply fertilizer more often than you do in the drier months.

Tip #10: Frequency based on plant deficiency signs

The last tip for when to apply fertilizer is to monitor your plants! Our vegetable crops will give us signs of deficiency, and let us know what they need! Here are a few signs to look out for:

Yellow leaves: This could indicate a nitrogen deficiency, so opt for a fertilizer high in nitrogen.

Purple leaves or stems: This may be a sign of phosphorus deficiency, so look for a fertilizer with higher levels of phosphorus.

Stunted growth: If your plants are not growing as they should, it may be due to potassium deficiency. Use fertilizers with higher levels of potassium to help boost growth.

Flowers dropping without setting fruit : This could indicate a calcium deficiency, so look for a fertilizer with higher levels of calcium.

By closely monitoring your plants and their growth, you can determine when they need additional nutrients and adjust your fertilization frequency accordingly. Remember to always follow the instructions on your chosen fertilizer and make adjustments based on your specific garden needs. 

Well, that’s all for this episode!

Keep these tips in mind when fertilizing your garden, and you’ll see healthy, thriving plants in no time! 

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Happy Gardening and Remember It’s never the wrong time to Grow where you are!

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