Tomatoes on a plant

How Often Can I Plant Tomatoes In The Same Soil?

Gardening is a labor of love but there are some ways to reduce the labor part, without reducing the love. In an ideal world most gardening manuals will tell you that you should rotate crops every season and replace compost after every use.

You would eventually get dozens of tomato harvests but it would take a lifetime and they would not be consecutive.

You might have noticed that in addition to extra trips to the garden center, lugging extra bags of compost or grow bags and the need to have a very large amount of beds. The yearly crop rotation will get expensive.

You might also want to take a more sustainable and self-sufficient approach to gardening, not buying in any more supplies than absolutely necessary.

What Actually Makes Tomatoes Grow?

Tomatoes require full sun to grow well and for most gardeners, that means you have a limited amount of beds that you could plant them in. In some gardens that might only be one bed. This will pose a problem for the traditional advice about crop rotation for tomatoes.

Typically you would be advised to leave two years in between planting tomatoes in the same spot. When you can’t wait that long for a homegrown tomato and you don’t have an alternative place to grow one, here is a guide to what you can do to work with what you’ve got. 

In theory, a growing medium should be able to be used again an infinite number of times. In practice, many repeated crops in the same soil could lead to a range of problems including poor yield from your plants.

Why You Can’t Just Replant In The Same Soil

You can exhaust the nutrients in your soil, the soil in a pot could become compacted and interfere with root systems for your tomatoes or pests could build up. None of that will help your crop of tomatoes thrive, in severe cases it could even kill the plants. 

You may have re-used soil many times before and be confused about why it would be a problem to re-sow in the same bed. For soil enriching plants or light feeders like legumes and leafy greens, you could re-sow repeatedly without major problems from your soil.

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With beans, peas and chard your biggest problem is likely to be that if you re-plant them in the same place, then the birds and bugs that like to eat them will know exactly where to look. Tomatoes in the same soil are unfortunately different.

You would find a similar problem with other crops from the nightshade plant family like eggplants. 

The maximum number of times you can grow tomatoes in the same soil will depend on a few factors. If all goes well though, most of the time you should get two harvests out of the same soil and from some you will be able to get up to four.

In rare circumstances, you may be able to get five or more, but at that point you might be better off investing effort into a vertical container garden, hanging basket tomatoes to take advantage of a sunny wall or window sill planting.

How Good Planning Gets The Most Out Of Your Tomatoes

Growing any plants works better with a little bit of planning. Tomatoes fit in with this rule of thumb. No matter where you grow tomatoes or in what medium, it will help to consider the essentials of what they need to thrive.

You need to keep an especially sharp eye on this when you are looking to re-use a growing space or your growing medium, because the nutrients and structure your soil needs will be in comparatively short supply. 

One of the major things you will need to do to increase the maximum number of times you can plant tomatoes in the same bed is to add nutrients back in.

Tomatoes are often called ‘heavy feeders’ which means that they take large amounts of vital chemicals and minerals out of the soil, compared to other plants, like medium feeding carrots or the nitrogen fixers like beans. Even the beginners among you probably already know that tomatoes are the kind of plant you have to feed. Empty tomato red bottles tend to haunt greenhouses. 

The reason this is important for you, wanting to know how many plantings you’ll get, is that your first crop of tomatoes will ‘drain’ your soil.

Universal Requirements For Plants To Grow – Almost Any Plant

All typical plants need potassium, phosphorus and nitrogen and after a single crop, your bed will be depleted. Especially when it comes to potassium and phosphorus because tomatoes need a greater ratio of these to nitrogen. This is particularly true when it comes to flowering and fruiting well. 

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In ‘fresh’ soil, meaning soil that you have not had a previous crop of tomatoes in within the last two years, you would normally feed your tomato plants once a week.

One of the most interventionist feeding regimes for common garden vegetables. That should give you an inkling, that re-using your soil will need you to take nutrient replacement seriously. Not just in between crops but with a regular feeding schedule and top ups of soil enrichers as you go. 

Commercial liquid feed should be fine for the regular feeds although many gardeners swear by their own blends of comfrey infusions with add ins like rabbit manure. 

An encouraging thing to bear in mind as you think about how to enrich your soil to get the tastiest tomatoes on a repeat sowing is that most tomatoes you buy from the supermarket are grown in mediums which carry almost none of their own nutrients, even hydroponics mediums.

How Are Home Grown Tomatoes Better Than Supermarket Tomatoes?

We all know that supermarket tomatoes don’t compete with the taste of home grown, but you can only gain when you start getting your hands dirty. 

The effort that will take you from being able to get away with a single second sowing to sowing year after year in the same soil should mostly be concentrated on the soil enhancement process.

This is not bad advice for gardening in general but it really goes double for tomatoes and other heavy feeding plants. There are a variety of things you could choose for enrichment but not all are created equal.

Good Options To Blend Up In The Soil To Make It Better

A natural soil additive like kelp can be great for upping the essential nutrients potassium, phosphorus and nitrogen in roughly the right ratios for tomatoes.

It can be dug directly into the soil or infused into a ‘tea’ to water the soil with, blended up in a kind of gardening smoothie to pour over the bed or added to your compost heap well in advance to be added as part of home made compost.

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Another good option would be wood ashes, if you have any wood ash going spare any time around thanksgiving or Christmas, scatter it onto your tomato bed for the next year and roughly dig it in. You’ll thank yourself in the summer.

If you don’t have the opportunity to keep a tub of comfrey or seaweed tea or even space for a small composter then there are still some options for you. Buy commercial tomato feed in advance and occasionally water the soil with some heavily diluted feed.

If you are growing a few tomatoes in an apartment or on a balcony in a container then you can help yourself by thinking ahead. 

Keep your coffee grounds and egg shells, blitz them up in a blender and put them into an old (and clearly labelled) ice cream tub in your freezer. When the time comes to plant your next crop of tomatoes, defrost the mixture and mix it in with your compost.

This could be done for an open soil bed too, but blending and freezing will not be necessary. This should get you at least a healthy second sowing from the same soil, if not two. 

If you want to get a second, third or fourth consecutive tomato crop out of your soil then you will need to consider structure as well as content. Soil can become compacted if it is in a container or simply become compressed and hard in a standard or raised garden bed.

Get a wheel barrow or a large garden trug and empty as much soil into it as possible from your tomato growing environment. This is a great opportunity to not only add fertilizers like rotted manure or bone meal but also to add a moderate amount of grit or sand to improve the drainage and structure of your soil.

Patience and the perfect tomato harvest

If you are a more patient soul, then you could try a scaled back crop rotation between tomato crops. Sow tomatoes for one summer, feed them in the conventional way then replace them in the autumn with a green mulch, dig that in then plant a legume for the following spring.

Return to the bed after one year of growing an alternative crop but shorten your ‘fallow’ time for tomatoes by deliberately and conscientiously replenishing your soil.

You could continue with this indefinitely as long as you were able to avoid any blight problems, in which case you must leave the bed fallow to recover.

You could also look at introducing companion plants and mycorrhizal fungi to ward off pests and improve your plants uptake of nutrients, particularly useful if you are looking to make the best of soil that has worked a few seasons. With a bit of ingenuity, you should be able to get more sowings and more tomatoes from one bit of soil.

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