Tomatoes, like many annual plants, are grown best when provided with plenty of nutrients throughout the season. Tomatoes need extra nutrients to increase, which can be provided by fertilisers. The question is: what are the best fertilisers for tomatoes and when is the best time to fertilise tomato plants? Our guide to fertilising tomatoes will answer all your questions.
Fertilising tomatoes the right way
Nitrogen, phosphorus, and potassium are the primary macronutrients tomato plants need, as are magnesium, calcium, boron, and zinc. These nutrients are needed in different ratios by tomatoes at different stages of their growth. It may seem daunting at first to fertilise tomatoes properly if you are new to gardening. The importance of soil nutrition cannot be overstated whether you are growing from seeds or seedlings.
I want to make one thing clear before we proceed: There is no single tomato fertiliser that works best for all gardens. Having such a thing would make gardening a breeze (and perhaps even boring). Based on the plant’s stage of growth, let’s take a look at some facts and fertiliser options.
Plant Fertilisation Basics for Tomatoes
- Tomato plants require different amounts of fertiliser depending on their stage of growth. The recommended ratio of nutrients changes with each stage of growth, but every nutrient must be present at all times.
- When mixing fertiliser into the soil, keep this in mind when mixing the roots of tomatoes. Fertiliser numbers are assigned to elements such as nitrogen-phosphorus-potassium (or N-P-K). For example, 10-8-10 means the fertiliser contains 10% nitrogen, 8% phosphorous, and 10% potassium, with the rest being filler.
Do tomato plants need specific fertiliser nutrients?
The building blocks of roots are phosphorus and potassium, while the building blocks of foliage are nitrogen and phosphorus.
- For roots and fruit to grow and develop, phosphorus is essential. Consequently, it plays a vital role at both the beginning and the end of the growth process.
- Foliage is taken care of by nitrogen, but too much nitrogen results in bushy plants with little or no fruit.
- Growing plants and producing fruit and flowers require potassium. However, it is essential for photosynthesis and disease tolerance.
Is fertiliser necessary for my tomato seedling?
There is no doubt about it – the tomato seedlings overgrow after they germinate, with an initial burst just before flowering. Within four months of planting, they usually bear fruit.
Fertiliser is also needed for full-grown plants.
The plant will give you cues as to what fertiliser it needs during this period (we’ll discuss this later). Many factors contribute to tomato requirements, such as soil type, weather conditions, and tomato variety.
Fertilising tomato seedlings during transplantation
Nitrogen is essential for plant growth. If your soil contains a lot of coconut husk or another kind of filler material, it will probably not contain enough nitrogen for plant growth.
What is the best way to determine whether or not my soil needs nitrogen?
If you test your soil, you can be sure for sure. Generally, you don’t need to add nitrogen to fresh compost – You just need to add phosphorus at the start of growth (right after transplanting seedlings). When your compost contains banana peel and bone, you may not even need to add phosphorus.
When transplanting tomato seedlings, there are two ways to add phosphorus.
In the case of phosphorus, it’s best to use a combination of bone meal and organic fertilizer spikes, but if you don’t want to use bone meal because it’s an animal product, measure your soil and add some traditional fertiliser.
- Bone Meal
It’s easy to use natural fertilizers like a bone meal while at the same time providing sufficient phosphorus to the tomato plants (which aids in fruit production).
This fertilizer is composed of ground-up bones, usually beef, but it may also contain other bones (like fish bones). The ratio of 3-15-0 is widely used in commercial bone meal products today. My favourite bone meal fertiliser is Jobe’s Organic 2-14-0. This mix also contains calcium, a micronutrient that prevents tomato blossom end rot. Furthermore, it prevents tomatoes from cracking and splitting by strengthening cell walls. It is a common problem and is easily preventable if you read my article on why tomatoes split before you get your first fruit.
- Fertiliser Spikes
Just after transplanting, it is highly recommended that you place Jobe’s organic fertilizer spikes 3 to 6 inches away from the stem of each plant. The soil’s nutrients are quickly depleted if you’re growing in a container.
Jobe’s fertilizers aren’t necessary; all you need is a spike containing a decent amount of nitrogen and potassium, along with a high percentage of phosphorous. To apply fertiliser spikes, push them into the soil. The average lifespan of these products is about two months.
How do I choose the best tomato fertiliser?
Depending on the soil’s nutrient content, you will need to choose a tomato fertiliser. Testing your soil is a good idea before fertilising tomatoes.
In the case of soils with high nitrogen levels, you should use a fertilizer that is slightly lower in nitrogen and higher in phosphorus, such as a 5-10-5 or a 5-10-10 mixed fertilizer. To make up for a slight nitrogen deficiency, use a balanced fertilizer like an 8-8-8 or a 10-10-10. The higher phosphorus tomato plant fertiliser can be used if you cannot get a soil test done unless your tomato plants have been sickly in the past. Make sure you don’t over-fertilise tomato plants with nitrogen. As a result, the tomato plant will be lush and green and produce very few tomatoes. If you have encountered this problem in the past, you might consider simply providing your tomato plants with phosphorus instead of a complete fertilizer.
Fertilising tomato plants at the right time
The first thing you should do when you plant tomatoes in the garden is fertilized them. Once they begin to set fruit, you can start fertilizing again. Until the first frost kills the tomato plants, add light fertilizer once every one to two weeks.
The Best Way to Fertilise Tomatoes
The tomato plant fertilizer should be mixed with the soil in the planting hole before the tomato plant is planted. The unfertilised soil should then be placed on top of this. It is possible to burn the tomato plant if natural fertiliser comes into contact with its roots. Water the tomato plant well before fertilizing it after the fruits have set. Tomato plants can burn if they are not watered well before being fertilised. Apply fertilizer to the ground after watering, starting approximately six inches (15 cm.) away from the base of the plant. Using fertilizer too close to a tomato plant can cause the fertilizer to run off onto the stem and burn the plant.
Tomato Fertiliser Needs During the Growth Phase (Pre-Flowering)
Indeterminate Tomato vs Determinate Tomato
It is possible to cater to the specific nutritional needs of determinate tomato plants during their growth phase and fruiting phase. With indeterminate types, this is not the case. The fertiliser you should use for indeterminate plants will be 8-32-16 or 6-24-24. In general, nitrogen makes up 1/4 of phosphorous and at least 1/2 of potassium. Determinate varieties are discussed in this guide.
Nitrogen needed for pre-flowering plants:
As your determinate varieties grow, nitrogen is essential to their growth because it aids the formation of genetic material and helps form many structures.
You won’t have to add nitrogen to your soil if it’s good and you’re using a lot of compost. It is a sign of nitrogen deficiency if you notice the bottom leaves of your tomato plants turning yellow. It should be noted that yellow leaves can also be the result of excess nitrogen. However, it is more likely to occur when there is a lack of nitrogen than an excess of nitrogen.
Compost is what I use at the beginning, and then compost tea is added two weeks later. As a result, sufficient nitrogen is provided, as well as some macro- and micronutrients that have been lost.
The time to add potassium is just before flowering to the end of the growing season.
To grow more flowers, your plant will need a constant supply of nitrogen-not too much, though, since overfeeding encourages the growth of leaves instead.
The most important thing, however, is that potassium fertilizer is needed at this time. Strong growth is promoted by potassium, an essential nutrient. The potassium level in your garden should be at least double that of the nitrogen level if you add fertilizer. If you want, you can add 8-32-16 or 6-24-24 according to the instructions on the pack, or you can make a compost tea the way I do.
Compost Fertiliser Tea with Potassium
The peels of bananas are rich in potassium, and they release it slowly when buried, assisting plant growth.
- Make banana peels by collecting a few bananas,
- The best way to do this is to chop them up (as shown in the image below)
- Please put them in the ground and bury them.
During the growth phase of your plant, collect banana peels and make the tea in a big container that you can cover so the smell of rot does not spread. As the season progresses, keep adding more peels.
Tomato Fertilization: From Flower to Ripe Fruit
Nitrogen is still needed during this phase, but not in large quantities. You don’t need to add any nitrogen to the soil if your plant has been growing well so far.
For good fruit, phosphorus is crucial. It would be best if you continued to drink potassium tea, but maybe once a week, not more. Most garden soil has sufficient phosphorus, and by this stage, your plant would have developed symbiotic relationships to acquire phosphorus if it had been planted in the ground. It is only through the experience of the first crop or by testing your soil that you learn whether you should add some of your fruit that is not developing well. If you add some phosphorus-rich fertilizer in the first year, it will not harm the plant. It will be a good idea to choose something like 8-32-16 at this time if you want to fertilize tomatoes.
Just before flowering:
The next step is to determine how long it takes to flower on average for your specific tomato variety. You can start putting some of the water you’ve been collecting in up to two weeks before this date. Your concentration and amount may determine how much you need to dilute or how often you need to use it. The best thing you can do is keep an eye on your plant. Stop adding more if you notice growth slowing down. If you monitor the plant, you’ll never go wrong.
To encourage symbiosis with tomatoes, use organic fertilisers.
It may be a good idea to consider Dr Earths Organic’s all-purpose fertilizer if you plan on planting in the ground (as opposed to in containers) to help your plants grow by symbiotically growing with the soil microbes.
When it comes to in-ground tomatoes, why is symbiosis important?
Mycorrhizal fungi, for example, transport phosphorous from the earth to tomato roots in exchange for sugar and starch. You can read more about other phosphorous sources on Grow It Organically, which is where I first learned about this.
You may not have to artificially induce symbiotic systems into an environment with a well-performing garden since they are already present. The only time I would recommend this is if your garden doesn’t grow green on its own or if a lot of new topsoils have been added.
Organic tomato fertiliser is beneficial for four reasons:
- Their ease of use makes them more convenient.
- Your local water table and the environment will benefit from it.
- The environment is less likely to be harmed by them.
- Overuse of chemical fertilisers (rather than natural, powdered rock) by inexperienced gardeners causes plants to “lockout,” the defence mechanism that prevents them from absorbing nutrients.
Conclusion
Tomatoes need a healthy supply of nutrients to grow. A good fertiliser can help you achieve that. High-phosphorus and potassium fertilisers are the best for tomatoes. For great-tasting tomatoes, these two nutrients are also crucial. Fertilizing must be done according to instructions and shouldn’t be overdone as over-fertilizing is more damaging than under-fertilizing.
To choose your fertiliser, I suggest considering your plant’s growth stage and soil analysis. Use a fertilizer with a low nitrogen and high phosphorus content if your soil is rich in nitrogen. You should use a balanced fertilizer if your soil lacks nitrogen.
FAQs
How do I choose the best fertiliser mix for tomatoes?
Nitrogen and phosphorus-rich fertiliser mixes are best for tomatoes. To grow tomatoes successfully, you need a fertiliser mix that contains a lot of nitrogen and phosphorus. Calcium, magnesium, and potassium should also be included.
Among the best fertilisers for tomatoes are manure, blood meal, cottonseed meal, bone meal, feather meal, fishmeal, and seaweed extract.
What type of fertiliser promotes the fastest growth of tomato plants?
You can grow more tomatoes in a season by using the right fertiliser. The types of fertilisers that work best for tomato plants are high-nitrogen, low-phosphorus, and low-potassium.
