First cultivated by the early Aztecs, tomatoes were introduced to European palates in the 1500s. Their original yellow and orange coloration evolved through selective breeding into the more familiar red. Luckily, heritage seeds for the originals were collected and preserved. While using them to expand those sunset hues into everything, from cherries to beefsteaks, to include a deep, rich purple.
Reaching that stage of mouth-watering perfection means that certain plant requirements have been maintained throughout each growth phase. This includes vital nutrients specific to this flavorful fruit. After extensive testing, I’ve narrowed down my picks for the seven best tomato fertilizers. Based on ease of use, performance, and consumer feedback. These, we’ll discuss in a moment.
- Top 3 Fertilizers for Tomato Plants
- Choosing the Best Fertilizer for Tomatoes
- 7 Best Tomato Fertilizers Reviewed
- 1. Jobe's | Tomato Fertilizer Spikes 6-18-6
- 2. Espoma | Tomato-tone Organic Fertilizer 3-4-6
- 3. Neptune's Harvest | Tomato & Veg Fertilizer 2-4-2
- 4. Dr. Earth | Home Grown Tomato & Vegetable Fertilizer 4-6-3
- 5. JR Peters | Jack's Classic 12-15-30 Tomato Feed
- 6. Miracle-Gro | Performance Organics Plant Nutrition 9-4-12
- 7. Miracle-Gro | Plant Food, Tomato Fertilizer 18-18-21
- Tomato Growing Stages
- Fertilizing Tomatoes Indoors and Outdoor
- How To Fertilize Tomatoes
- When To Fertilize Tomatoes
- Verdict: Best Fertilizer for Tomatoes
- FAQs Fertilizing Tomatoes
Top 3 Fertilizers for Tomato Plants
If you’re in a rush to find the best option for your tomato plants, here are my top recommendations:
Best Fertilizer Spikes For Tomatoes
Convenient pre-measured fertilizer spikes. Designed to be pushed an inch into the soil to provide a slow-release feed right through the growing season.
Best Tomato Fertilizer For All Growth Stages
Slow-release organic granules with Espoma’s patented Bio-Tone blend. Formulated to reduce the risk of disease and increase the yield and size of crops.
Best Liquid Fertilizer For Tomatoes
Fast-Acting liquid, loaded with additional organic macro-nutrients such as fishmeal and humic acid. Expect lush foliage and tolerance against disease & drought.
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Choosing the Best Fertilizer for Tomatoes
Out of all the options that I tested, the best tomato fertilizers were either specifically formulated for them or had an inclusive N-P-K relative to their needs. Having added an all-purpose feed and no feed at all to the mix, I can say with all confidence that for healthy bountiful tomato plants, at least a partial focus on tomatoes is crucial.
Tomatoes reach peak performance with access to the right combination of macronutrients. Nitrogen (N) – for chlorophyll production and photosynthesis, phosphorus (P) – for robust stems, leaves, and fruit, and potassium (K) – for nutrient distribution and vibrant fruit color.
Fertilizer labels will include three numbers separated by dashes. These are the N-P-K ratio of that fertilizer. Indicating its proportions of nitrogen, phosphorus, and potassium, in that order.
The best fertilizer for tomatoes will also include secondary trace elements and micronutrients such as magnesium, calcium, and zinc. These together with a solid NPK will support your plants in each stage of growth.
Now, if you regularly add well-aged compost to your soil, it’ll already have a healthy percentage of all those necessary macronutrients. In this case the best NPK for your tomatoes will be one that has a relatively even balance of nitrogen, phosphorus, and potassium. This will prevent overfeeding and plant damage. If you don’t compost regularly, that’s ok. But just remember to boost the NPK in order to improve less fertile soil conditions.
Granules Vs Liquid Fertilizer
The difference between these two methods is simply a matter of what works best for you. Quick-release options typically come in a water-soluble form that conveys nutrients immediately. This can result in accelerated improvement for plants growing in less-than-desirable soil. But, caution is recommended, as over-feeding is common and could lead to root burn.
Heavily concentrated, slow-release options offer a steady stream of nutrients over an extended period of time. Rather than inundating your plants with high doses of nutrients all at once. No watering is needed to activate and are less likely to leach into nearby water sources.
A water-diluted dose of concentrated, liquid nutrients can work through either quick root absorption or as a foliar spray. Cost-effective and time-saving, this type allows for simultaneous watering and nourishment and gives you more control over how much is applied and when. The effect is almost immediate, which is especially beneficial for those living with shorter growing seasons. Liquid options are also typically less expensive and help to maintain a balanced soil pH.
Granules, spread around the base of plants by hand, release nutrients with every watering or period of rainfall. Soil microorganisms convert these into a form that can be easily absorbed by plants.
Slow-releasing, pre-measured spikes are even easier to use. After pushing these into the soil, nutrients are released by those same soil microorganisms. This particular method of application also carries the added benefit of stimulating an increased resistance to disease and pests.
Organic Tomato Fertilizer
For purely organic growing, nothing provides a more fertile, slow-releasing option than well-aged compost. This effective soil conditioner contains a generous amount of nitrogen plus beneficial trace minerals that won’t overwhelm your plants. Adding this also improves moisture retention and drainage properties in sand or clay-based soils.
Fish emulsion is another high nitrogen source that nourishes plants and conditions poor soil. If less is needed, worm castings offer enough gentle nitrogen and trace elements to satisfy most fruiting plants. When a boost of organic phosphorus and potassium is needed, kelp meal and hardwood ashes are popular options.
Ideal pH for Tomatoes
Tomatoes prefer a pH range of 6.0 – 6.5. They’ll still grow if the pH is a little outside this. They just may not be able to absorb nutrients as efficiently. Anything drastically above will block access to nutrients entirely. Too low (overly acidic) and your plants will become vulnerable to the effects of damaging heavy metals in the soil that inhibit photosynthesis.
A bit of lime will increase your pH if needed. And elemental sulfur will lower it. The best fertilizer for tomatoes, though, will have pH balancing properties already built-in.
7 Best Tomato Fertilizers Reviewed
So now on to my picks for the seven best tomato fertilizers based on ease of use, performance, and consumer feedback. These were all tested on different tomato varieties in my own garden. Some of which I grew in the ground and some in pots.
- Continuous nourishment for 8 weeks
- No wasteful runoff
- Safe to use around pets once buried in the soil
- Not as cost effective as other fertilizing methods
I found this method of fertilizing the easiest to use. These 3-inch long ‘spikes’ are perfect for container gardening. I used them around some potted cherry tomatoes and the increased phosphorus resulted in large, scalloped leaves and strong stems to hold up all those long vines of tiny tomatoes.
Even though I add compost to my potting soil, these plants typically use up all the inherent nutrients pretty quickly. But by adding a couple of Jobe’s spikes around your potted plants you can expect an increase in flowering and fruit production for up to eight weeks. With no runoff or waste and zero ‘organic’ smells since the spikes are buried in the soil.
I would recommend these to beginner tomato growers for their ease of use and visible results. They also come in a waterproof, resealable pouch which makes for easy storage.
How To Use: Insert spikes around the plants and the slow-release formula feeds your tomato plants for up to 8 weeks.
Customer Reviews: Container gardeners can’t say enough about Jobe’s spikes. Plants in pots deplete the soil of nutrients much faster and these spikes make replacing them very easy. Granting this option 4.6 / 5 stars.
- Exclusive Biotone formula
- 8% calcium to protect against blossom end rot
- Contains a variety of beneficial bacteria microbes
- Strong organic smell
Espoma Organic Tomato-tone with its exclusive Biotone formula proved to be just the right NPK ratio to support ground-planted Roma tomatoes at each stage of growth. Regular applications right from the planting stage up until harvest resulted in healthy green foliage, abundant flowers, and vibrant fruit color. Plus the added bonus of extra calcium to prevent bottom rot in case I over-watered a bit.
Tomato-tone proved most effective when I worked it into the soil, 3” from the plant’s stem, and watered it in thoroughly. Considered a slow-release formula, its natural and organic ingredients work faster than others. So, you do have to apply it every two to three weeks. I personally felt this effort was worth it considering the size of my Romas.
How To Use: Apply the recommended dosage for single plants, potted plants, and ground plantings, then water thoroughly. Repeat twice per month from May to August.
Customer Reviews: Gardeners trying to grow tomatoes in less-than-fertile soil go straight to Tomato-Tone. And the extra calcium prevents bottom rot when overwatering occurs, for beautiful fruit and improved soil. 4.7 / 5 stars.
- Contains fish meal, molasses, yucca extract, seaweed, and humic acids
- Increases tolerance to high temperatures and drought
- Ideal for vegetables, trees, shrubs, and flowers
- Not recommended for use on young seedlings
This relatively new option from Neptune’s harvest is organically formulated for tomatoes and many other vegetables that experience intense growth in various stages. Made with fishmeal, seaweed, and humic acid, this low ratio combination was perfect to use around my red beefsteak tomatoes.
The soil here I amended with compost so this organic option didn’t overwhelm my plants. The resulting thicker stalks were able to support much bigger or more vibrant tomatoes. The wider expanding roots and lush foliage allowed for optimum photosynthesis. Increasing each plant’s tolerance against disease and environmental stresses.
The jug apparently has an indefinite shelf-life too. Which means I can re-use it next year.
How To Use: Mix 1/8th cup per gallon of water and apply to plants. Repeat every 2-3 weeks.
Customer Reviews: Home growers with small gardens absolutely love how long this one jug lasts. And the purely organic results can’t be beaten. Great value for money for organic gardeners. 4.8 / 5 stars.
Best Organic Tomato Fertilizer For Balanced Soil
- Advanced probiotic formula
- Can be applied dry or used as a tea spray
- Lasts up to 8 weeks
- Not ideal for indoor tomato plants (due to the the ‘organic’ smell)
My first pick from Dr. Earth is popular in organic gardening. With no synthetic or GMO ingredients, nutrients are naturally broken down by beneficial soil microbes and slow-released to roots for absorption as they are needed. This is an ideal fertilizer to use for established tomato plants from stage two onwards, provided they are already planted in nutrient-rich soil.
The low NPK proportions enabled me to use this on my tomato plants but also as a general-purpose vegetable fertilizer as well. After a couple of applications on my Heirloom tomatoes, my soil fertility increased as did my plant’s tolerance to some brutally hot days. And the number of heirloom tomatoes that I got, that I could then save seeds from, was far more abundant than expected.
How To Use: Side dress ¾ to 1-½ cups for every 10 sq. ft. of growing area. Then, repeat every 2 months throughout the growing season.
Customer Reviews: Consumers are calling Dr. Earth’s tomato fertilizer “foolproof” with impressive value for money considering how little is needed for such wonderful, organic results. Coupled with its ease of use, this is my choice for BEST BUY. 4.6 / 5 stars.
- Optimum combination of nutrients for fruiting vine vegetables
- Contains a higher amount of potassium and magnesium
- Contains calcium to help prevent blossom end rot
- May be at a higher price point than other options
Jack’s classic FeED is also well-suited to those plants growing in less fertile soil but as a water-soluble option. Its 12-15-30 NPK offers increased proportions of all vital macronutrients to support health and vitality at each stage of growth.
Because of these high percentages, I held off on adding more compost to the soil around my green beefsteak tomatoes. Then, I watered them every week with a dose of Jack’s. The effects were visible within a few days due to the addition of magnesium. And the calcium prevented blossom rot on these large beauties. My fried green tomatoes were juicy and flavourful.
How To Use: Mix the recommended amount with water and apply with a watering can, hose attachment, or spray bottle. Repeat every 7-10 days.
Customer Reviews: Even staunch organic growers feel comfortable adding a bit of Jack’s to their plants. The quick and effective results plus improved soil conditions had them sold. 4.7 / 5 stars.
- Visible results in seven days
- Formulated for tomatoes and other vegetables
- Not recommended for use in fertile soil
This nitrogen and potassium-heavy offering from Miracle grow is formulated to support not only tomatoes but all of your other vegetables and herbs, as well. This seemed the perfect NPK to support healthy plants in less-than-desirable soil. So, I planted some tomatillo seedlings in plain potting soil without adding compost. And to my surprise, the number of healthy fruit I got far exceeded past years of attempting to grow these.
I simply sprinkled the recommended dose around the rim of each pot, water it in well, and began seeing a difference by the end of the first week. An organic option from a dependable but typically non-organic brand is fantastic.
How To Use: Mix the recommended amount into the top 1-3” of soil around the base of each plant. Water thoroughly then repeat every 4-6 weeks.
Customer Reviews: Miracle-Gro advocates are so pleased that they now have an organic product that offers the same dependable results. Agreeing higher levels of nitrogen and potassium are perfect for less-than-fertile soil. 4.5 / 5 stars.
- Safe for all plants, guaranteed not to burn when used as directed
- Balanced blend of macro and micro-nutrients
- Grows bigger, more bountiful vegetables versus unfed plants
- Not ideal for plants that have calcium deficiencies
This water-soluble option from MiracleGro has been a trusted staple in many gardens for years. The high percentage of vital macronutrients makes it versatile enough to use in all different types of soil. Absorbed through roots and foliage, this balanced plant food can be applied using a simple watering can or hose attachment.
The robust NPK is effective on tomatoes and most other vegetables and is safe against root burn when used as directed and applied every two weeks. But, while it does contain an added blend of micronutrients, it may not have enough calcium to prevent bottom rot on tomatoes.
How To Use: Mix 1 tablespoon per 1 gallon of water and apply every 7 to 14 days during the growing season.
Customer Reviews: Gardeners growing tomatoes in containers are reporting their harvest continuing long after they bring the pots indoors for the winter. An extended harvest of bigger, tastier tomatoes earns this choice 4.7 / 5 stars.
Tomato Growing Stages
There may be as many as 12 different ‘micro’ stages of growth in the life of a tomato plant. But for home-growers, there are three that pertain directly to proper fertilization. Understanding how the feed we offer them works in each stage leads to a successful harvest and the ability to avoid common issues. These are:
- Leafing Stage – Starting at the point of seed germination, roots and foliage growth begins. Nitrogen is critical to efficient chlorophyll production and photosynthesis in new leaves and stems.
- Flowering Stage – Blossom formation is fueled by adequate levels of phosphorus. This macronutrient also supports strong cell walls for robust stems and fruit.
- Fruiting Stage – As flowers become fruit, potassium is vital to prevent blooms from failing and falling off.
Fertilizing Tomatoes Indoors and Outdoor
The best tomato assortment to grow indoors are those that are smaller and grow well in one pot that’s of a manageable size. These are vining, ‘indeterminate’ types like plum, cherry, and grape tomatoes. Because of their limited growing space, indoor tomatoes will typically absorb nutrients faster than those in the ground outside. Making slow-releasing options the best fertilizers for these tomatoes, ensuring a consistent stream of nutrients.
Bushy outdoor varieties, or ‘determinates’, are heavier feeders than indoor, smaller ones and therefore may require a higher dose of fertilizer, along with more room to grow. In this case, both slow-release and quick-action feed work well. Regardless of location, feeding your plants the right NPK at the right time will lead to success.
Tomatoes in Pots and Containers
Tomatoes are some of the heaviest feeding fruits. For tomatoes, potting soil alone may not be enough. A significant amount of compost and other organic material will help maintain a healthy growing environment. Especially when you can’t fertilize them right away.
When transplanting seedlings, adding a handful of fertilizer in the hole before adding the seedling will ensure that the roots are nourished and experience as little trauma from being moved as possible. Then repeat feeding every two weeks with a liquid option or longer with granules or spikes.
Tomatoes in Greenhouse
The unique environment that a greenhouse offers our tomato plants is a little different than what those grown in the ground or indoors get. Greenhouses provide optimum sunshine and warmth which aid in photosynthesis and stimulate vigorous growth. This all leads to an abundance of large, juicy tomatoes.
But because of this easy access to light and warmth, greenhouse plants start to process nutrients much faster and can also dry out faster. This means they may need more frequent watering and feeding. Luckily, there are fertilizers on the market that are specifically formulated for greenhouse plants that support this type of growing.
How To Fertilize Tomatoes
As we’ve seen, you’ll want to make sure that your tomatoes, no matter the variety, are receiving the right amount of macronutrients at the right stage. This will support the profusion of inner activity required to produce beautiful, healthy fruit. This means plenty of nitrogen, to start. An abundance of foliage, when you should see flowers, may mean it’s time to pull back on it.
More phosphorus is needed to stimulate bud formation. Make sure your plants are getting lots of sunshine as this is what triggers your plants to use that phosphorus. Long periods of cloudy skies can often be the cause of delayed flowering. And finally, adequate potassium levels are required to get those flowers to become vibrant fruit. Although, poor pollination could inhibit this.
How Often to Feed Tomatoes
How often you fertilize, over the course of a season, will depend on your chosen application method. Water-soluble options often need to be applied more frequently. Especially for tomatoes grown in pots or other containers. Nutrients get absorbed far faster in these than in the ground and runoff is also common with frequent watering. For those grown in greenhouses, the absorption rate can be even quicker due to the increased vigor in growth. Most water-soluble options recommend fertilizing every 2 weeks.
Slow-release spikes and granules, which offer a more gradual but consistent release of nutrients, generally recommend repeat applications every 4-8 weeks.
Over Fertilizing Tomatoes
Starting new plants off with a granular formula is the easiest way to help prevent over-fertilizing. However, when directions are followed with water-soluble options, the same benefits can follow.
When over-fertilization occurs, more common in potted plants, there are certain visible symptoms that will indicate an issue.
- Little to no growth
- Yellowing leaves
- No flowers or dropped flowers
- A crust forming on the soil’s surface
- No fruit
If you suspect over-fertilization, the best course of action is to “flush” the soil of any extra liquid nutrients that may have been applied by simply watering, with nothing added, for the next couple of weeks.
When To Fertilize Tomatoes
When growing tomatoes from seed, fertilizing isn’t necessary until the seedlings are either repotted or placed in the ground when the weather warms up in spring. The second dose can then be applied when the plants begin flowering. Then, feeding can continue until fruit sets in early to mid-summer. Once plants begin fruiting, doses can be administered farther apart until mid-August, just before the picking of tomatoes for harvest.
This will prevent overwhelming your tomato plants and allow them to refocus their energy on ripening existing fruit. Rather than stimulating it to grow new stems and leaves, that takes away from that process. This same schedule can be effective whether you’re using slowing-releasing spikes or granules or a fast-acting liquid.
Verdict: Best Fertilizer for Tomatoes
The verdict is in! The best fertilizer for all tomato varieties is one that supports each stage of growth and gives you the abundant harvest you’re striving for. As a recap: In nutrient-rich soil, a lower ratio of NPK macronutrients will ensure gentle nourishment without the risk of overfeeding. In poor soil, a higher ratio will support your plants toward higher productivity and vitality.
Remember to plant in soil that is rich in organic matter and add supplementary nitrogen if needed. Increase phosphorus once plants are established in order to encourage bud set. Then once flowers begin to show it’s time to increase levels of potassium to stimulate that all-important fruit production.
Best Fertilizer Spikes For Tomatoes
Convenient pre-measured fertilizer spikes are designed to be pushed an inch into the soil to provide a slow-release feed right through the growing season.
My number one choice and the overall favorite for best tomato fertilizers is Jobe’s Tomato Fertilizer Spikes. It is not only perfect for both container and ground-grown tomato plants but can also be used from day one of planting and right throughout each stage of the tomato-growing life cycle.