To get the biggest, sweetest, and tastiest carrots, they need good nutrition – so, without further ado, we’re sharing our recommendations for the best carrot fertilizers on the market.
Carrots are a great addition to any vegetable garden! They thrive in sunny conditions, take up very little space, grow vigorously, and enjoy cool temperatures (75-50 degrees Fahrenheit), making them a perfect early spring or fall crop.
Best Carrot Fertilizers for 2021
Carrot Fertilizer Requirements
Carrots are root vegetables, and the tuber we love to snack on is the plant’s way of storing all the nutrients it can pull out of the soil – a bit like the plant’s pantry!
So, the more nutrient-rich your soil is, the bigger and faster your carrots will grow, and the tastier your crop will be. However, it’s not as simple as dumping lots of carrot fertilizer on your crop, as this can damage the plants – it’s about giving them the right amounts of the right fertilizer for carrots on a regular basis.
Generally, carrots will grow well in good soil, so start by prepping your beds with plenty of organic compost and organic mulch (you can use Gorilla hair, bark, leaf mulch, or grass clippings from your lawn), especially if you have very clay or very sandy soil.
This will give your carrots a good start. When the tops/frond have reached a height of 3 inches tall, you can boost growth with a granular or liquid fertilizer.
How Do You Know When to Harvest Carrots?
Carrots can be harvested early at about 60 days if you want snack-sized baby carrots, and around 80 days if you want mature, large carrots.
If you want to know if your carrots are ready to harvest, you can gently dig one up (they can be replanted quite easily) or gently uncover the top of the carrot to check the diameter.
They should be a rich, bright orange (although you do get different color rainbow carrots as well as fascinating and delicious heirloom species that are wonderful to grow!) and around ¾-1 inch in diameter.
How to Choose a Fertilizer for Carrots?
The fertilizer you use should be relatively low in nitrogen and higher in potassium and phosphate. Nitrogen tends to boost leaf and green growth, while potassium and phosphate is more supportive of root/tuber development.
Fertilizers have a set of 3 numbers in their name. This is the ratio of nitrogen (N) to phosphate (P2O5) to potassium(K). Good fertilizers for carrots include a 0-10-10 or 5-15-15 fertilizer. If the number is not visible, look for a fertilizer specifically designed for vegetable gardens.
How to Test the Nutrient Levels in Your Soil?
While the general rule is that the carrot fertilizers mentioned above are the best, it’s also a good idea to test your soil first to see what the nutrient content is before you start fertilizing carrots, as this will help you make a better decision.
For example, if you test your soil and it has a good amount of nitrogen in it already, it will be better to choose a 0-10-10 than a 5-15-15 because you don’t need the additional nitrogen.
The easiest way to test your soil is to perform a simple soil test analysis with a soil test kit. You can do this before you prepare your planting beds as well as after.
Remember to do several tests in different areas of the planting bed to get a better idea of the condition of your soil as a whole. These tests are safe, easy to use, and give you results in just a few minutes.
Carrot Planting Tips & How to Fertilize Carrots
- Plant in early spring or early fall, when day time temperatures are around 75 and nighttime temperatures are around 50 degrees Fahrenheit.
If you’re worried about cooler temperatures, cover your crop with a few inches of straw or pine needle mulch to keep the soil warmer – just make sure the tops still get sunshine.
- Start by digging over your vegetable garden bed, loosening the soil up by digging eight to twelve inches in depth, and adding lots of compost. You should plow the soil before planting.
If your garden soil is not hard or you don't want to take a lot time, so a small tiller is the best to loosen the soil.
- After that, you can spread the carrot fertilizer by using approximately 1 cup for every ten feet of soil.
- Using a cultivator, tiller or a garden rake, start mixing the carrot fertilizer within the three to four inches of soil. Distribute it as evenly as possible to ensure that there are no pockets that are concentrated, which could burn the carrots.
- Start planting the seeds into rows, with each seed 4 inches deep in the soil and spaced 3 inches apart. The carrot fronds should emerge in about 14 days.
- Sprinkle the fertilizer over the area where the carrots are growing. You need to ensure that you are using two tablespoons of fertilizer for every ten feet per row.
You can mix the granules with the soil using gloves. This helps make sure the granules won’t be washed away when it rains.
- The carrots can be harvested at any time after about 60-80 days depending on whether you want baby carrots or a larger size.
- Throughout the growth season, keep checking the topmost leaves. If they look pale rather than a vibrant, deep green, repeat the fertilizer application.
Get to Know the Best Carrot Fertilizers
Growing carrots is easy for beginners and experienced gardeners, as they thrive in vegetable garden beds, containers, and in small gaps around your garden.
Remember, the best carrot fertilizer is one that improves the current condition of your soil and creates the right low nitrogen, high potassium, and high phosphate environment for your carrots, so test your soil before you buy!
Here are our recommendations for the best fertilizers for carrots.
Also called NPK fertilizers, these granular fertilizers are typically manufactured, chemical fertilizers – although there are some great natural ingredient options too.
As we’ve mentioned above, these will have the nitrogen, phosphorus and potassium ratio on the packaging, and supply your carrots with the macronutrients they need to grow.
The best option for carrots has a low amount of nitrogen and higher amounts of phosphorus and potassium, and includes options like a 5-10-10, 1-2-2, 3-4-4, or 5-15-15.
This 36lbs bag is a great option for vegetable gardens and is made of a complex blend of natural and organic ingredients. It’s enhanced with beneficial microbes to help improve soil health and prevent diseases, and it is slow release, so it provides a consistent supply over a couple of weeks.
It’s quite a smelly mix, but the plants love it! Just remember to keep your pets from eating it, as it’s quite attractive to them and although it’s organic it will create some upset stomachs!
This fast-acting fertilizer is listed organic by the USDA, so there are no synthetic chemicals in the mix. It’s enhanced with Jobe Biozome, microorganisms that break down organic materials in the soil quickly, improving soil quality and releasing nutrients for your carrots and other vegetable or fruit crops.
It will help improve the flavor and yield of your crop, as well as improving disease and pest resistance. What’s more, it comes with a 90-day money-back/replacement guarantee if you aren’t satisfied with the results.
Be careful not to over-use this fertilizer on your garden, as high amounts of NPK can leach into nearby water systems and environments, affecting wildlife, local flora and water quality.
Kelp fertilizers are a great addition to your vegetable garden, supplying essential micronutrients like boron, magnesium, and calcium for your growing carrots.
These nutrients are essential for producing chlorophyll, keeping leaves healthy, and improving nutrient uptake from the soil. When the soil is low in calcium, carrot leaves can wither off.
If it is low in boron, then the leaves can start displaying rosettes and changing color as they mature.
Made with organic, natural cold water Norwegian kelp, your carrots will love this seaweed-based fertilizer. It’s infused with beneficial microbes to help improve nutrient uptake and soil quality, and it’s an excellent source of potash!
It’s kelp flakes rather than a liquid fertilizer, so it’s easy to apply and a bit less smelly than other options. It breaks down as you water it, supplying potassium directly to your carrots and vegetable crops.
Another great natural kelp fertilizer is this option from Fox Farm. It’s an all-natural, organic liquid fertilizer made with Norwegian kelp. It’s a little smelly, but safe for kids, pets and the environment – though you should stick to manufacturer recommendations for application.
You can use it on all plants, from roses and fruit trees to carrots, vegetables and indoor plants.
This liquid kelp fertilizer is made from organic seaweed (Ascophyllum nodosum) sourced from the North Atlantic Ocean. It is a concentrated fertilizer with 16 ounces making 32 gallons (we recommend diluting it even further to double this) and covering around 1000 square feet.
You can apply it every 1-2 weeks or as needed, and it feeds carrot and vegetable crops as well as flowering plants, shrubs and trees. It does have a seaweed smell, but the results are more than worth it!
Be careful not to over apply these fertilizers, as it can cause the carrots to become fibrous.
Potash is the main source of potassium in fertilizers, so if your soil has tested low for potassium, then potash is exactly what you need to add.
This essential nutrient helps improve the uptake of water into the plant, improves the production of carbohydrates to make larger, sweeter carrots, and regulates growth so that your carrots grow evenly to their full size.
If your soil is very low in potash, then you will see issues like stunted, malformed carrots, yellowing, burnt-looking leaves, and greater vulnerability to diseases and pests.
This all-natural, OMRI-listed fertilizer has a 0-0-22 formula, supplying plenty of potash for vegetable gardens low in potassium. It is a crystalline substance that is fully water-soluble, and supplies magnesium and sulfur as well as potassium.
It has a maximum of 3% chlorine (naturally occurring in potash) to prevent burning your plants, and offers the best in organic nutrients in ideal proportions without using synthetics, growth stimulants or low quality fillers.
We also really like this 0-0-50 OMRI-certified organic solution of potassium sulphate. It’s a premium product, so it’s fairly expensive, which is the only downside. It’s important to do a soil test before you use this, as it is a high-yield formula.
If your soil is only slightly deficient, you can dilute it considerably. It contains magnesium and sulfur as well as potassium in the balanced formula, and it can be used in gardens as well as reservoirs, fertigation, spray and drip irrigation applications.
If your soil is low in potassium, then this is a good-quality product that’s easy to apply and will improve your soil quality. It’s affordable, has a 0-0-60 high-yield formulation, and is designed for all vegetables, including carrots and potato crops, as well as flowering plants.
4lbs of this product will cover 800 square feet, using 0.5lbs per 100 square feet of vegetable garden. A good rule of thumb is that alkaline soils will not need potash, while acidic soils do.
Adding potash will help bring the pH to the neutral/alkaline side if you want to correct your soil. As with the other carrot fertilizers, do not overuse potassium fertilizer, as it can kill aquatic organisms if it washes away into waterways.
Here’s a great video on how to apply your chosen fertilizer to your vegetable garden beds.
Grow the Tastiest Vegetables in Town with the Best Carrot Fertilizers!
Carrots are easy and fuss-free vegetables that anyone can grow, as long as you prepare your soil and plant them in a sunny spot.
You’ll enjoy tastier, faster-growing crops this spring and fall if you test your soil before planting, and tailor your fertilizer to what carrots need (low nitrogen and higher in potassium and phosphate) and what’s lacking in your soil.
You can improve the pH to a neutral or slightly alkaline soil by adding potash/potassium too. Remember, a sunny spot and not overusing carrot fertilizer will get you the best results!