Grafted Vegetable Plants: The Pros & Cons of Grafted Vegetable Plants

Are Grafted Vegetable Plants Worth The Extra Money? Tomatoes, Cucumbers, Peppers, Chillis, Melons, Aubergines & Courgettes Are Now Grafted. But Why Graft? Is Grafting Worth It?

Grafted vegetable plants have been around for a long time. Grafted trees go back millennia. Commercial growers have been grafting some crops for quite a while. But are they worth it for gardeners? What are the pros and cons? Are they a viable proposition or are we being conned?

Let’s start with the basics.

What is Grafting? How Do We Graft a Plant?

Grafting is the art or science of physically combining two plants so that they become one plant that is better than each of the individual plants. For example, the roots of some wild plant varieties may resist some root diseases but not give good fruit crops, whilst the modern varieties have good yields of fruit but are prone to get root diseases. If we could combine the two we’d have a much better plant that is both resistant to root diseases AND produces good yields of excellent fruit.

Some roots (in the trade we call them rootstocks) grow less vigorous trees when grafted with high yielding plants. This is actually a good thing when growing crops such as apples.  It gives us smaller trees, that give good yields but are easier to manage and pick. The use of “dwarfing” rootstocks have been used for a century or more. The rootstock control’s the size of the tree. For example, rootstock M27 (M stands for Malling, the research station where it was developed) produces stepover trees and spindle bushes that never exceed 4-6 feet in height whilst the full-sized tree may be 35 feet in height.

Rootstock MM111 is much more vigorous and produce a standard of half standard of the same variety. In this case, the tree will be around 15 feet tall.

Grafting entails taking a bud or scion (a small cutting or twig) and physically joining it to the rootstock. I’ll not go into the full details here except to say it’s not a terribly complex procedure and anyone can learn it quite quickly.

What Other Plants Can Be Grafted?

Olives, damsons. plums, nectarines, gages, apricots and many types of vegetables can be grafted. Vegetables include tomatoes, aubergine, peppers, chillis, cucumber, courgette, squash, watermelon & melon. Many commercial growers use grafted plants to combat certain root diseases, pests and leaf diseases; increase yields and generally promote plant vigour.

Why Graft Vegetables and Fruit?

There are many reasons to use grafted plants. As mentioned above the overall vigour of the plant can be improved which can increase yields, reduce disease potential and increase commercial profits.  And this works well for commercial growers who use the latest technology to maximise crop yields over a long growing season.

Seed companies are now offering gardeners grafted plants with a wide range of species and varieties being made available. One company emailed me with the claim “Grafted for 75% more fruit, quality, flavour and longer crops”.

An article I read promised longer seasons and the ability to grow without heat.

Let’s examine these promises.

Do Grafted Vegetable Plants Deliver Better Results?

As a retired commercial grower, I have to say the answer is rather mixed.  Grafted plants certainly work for commercial growers that use technology to closely monitor and manage temperature, light levels, humidity and plant nutrition. These growers invest significant sums of money into their growing environment. They conduct research themselves and monitor research from horticultural research stations internationally to enable them to have the edge when growing these high-value crops.  Even an increase as small as a few per cent can make commercial sense to them and will pay for the extra costs of procuring grafted plants.

But for the gardener, amateur grower and even commercial grower without the latest managed greenhouses, the answer is somewhat different.  Many of the claims do not stand up to scrutiny for gardeners. 

The thing is the claims the seed houses make apply to commercial growers that use this high-end tech to produce near-perfect growing conditions.

As gardeners and allotment growers we can’t produce these conditions,

Let’s examine some of the claims from a gardeners perspective.

Root Diseases

There are a number of root diseases that affect species such as those offered. They often build up in the soil and infect subsequent crops unless adequate time has elapsed between susceptible crops. A traditional alternative to using grafted rootstocks has been to sterilise the soil with steam or chemicals. This is costly and takes time. So grafted crops can make an economic difference to commercial growers.

The amateur grower can overcome soil-borne diseases by using grow bags, pot grown plants, hydroponics or similar.

In my own case, I’ve grown tomatoes for many years in the same border soil in my greenhouse and the amount of soil-borne disease is negligible. In fact, it is so low that I’ve not noticed any decrease in yield to date.

There is no point in using grafted plants to combat problems that don’t exist. And if they do exist there are several options that need to be considered alongside grafted plants.

Increased Yields

The majority of gardeners I see growing crops such as tomatoes can certainly improve their yields. They can do this by better understanding how to manage the crop, how to improve crop nutrition, how to improve crop irrigation (watering) and how to improve the growing environment including humidity and temperature.

Only when all these factors are optimised would it be worth considering using grafted plants.

As a retired commercial tomato and salads grower, I have to say that even with my experience of growing 100,000 or more tomato plants I am unable to achieve the same level of crop performance in my garden that I achieved under commercial conditions. Grafted plants, even with my level of expertise, would be totally wasted in my garden.

And anyone that has the potential to increase yields by 75% is clearly not doing the job well at present! Using grafted plants in the same conditions is extremely unlikely to improve crop yields this much.

Fruit Quality

Commercial seed producers are extremely good at producing varieties that exhibit good quality. Any variety that is substandard never gets to see the light of day.

So claiming that fruit quality is better is very dubious in my view. This is especially the case when we’ve seen a movement where consumers have rebelled against wonky fruit being ploughed back into the soil. The consumer claims that they taste just the same .. which they do .. and are happy to buy them. So are they really likely to obsess over wanting to improve quality even more?

And can it be improved much more anyway?  On the few times I see poor quality fruit it is normally down to poor growing techniques and not the need to use grafted plants.

Longer Growing Season

Seed companies claim you’ll get a longer growing season with grafted plants. And if you are a commercial grower they are right in very few situations. But commercial growers already get long growing seasons out of existing varieties.

What gardeners often don’t realise is that a commercial tomato grower is likely to plant their crop well before Christmas and will be harvesting it early in the new year and keep picking fruit until the day they rip it out. And that is likely to be a few days before they replant with the next season’s crops. So, if they are already growing crops 50 weeks of the year, how are they going to get longer crops. longer growing seasons?

Grafted crops are unlikely to give longer growing seasons to commercial growers. For gardeners, it is also unlikely that the season can be extended for most crops. What limits crops such as toms, cues, peppers and other warmth-loving crops is the gardener’s inability to provide enough warmth in their greenhouses or tunnels. Plus the fact they cannot employ the cultural methods professional growers use to grow these crops. A long season tomato is going to have a 10-metre long stem .. how can a gardener cope with that in a greenhouse that is only just above head height?

Commercial growers employ a technique called layering and it needs a lot of space to do well.  Gardeners can’t achieve this in small greenhouses.

Improved Flavour

It has to be said that flavour has suffered a lot over recent years. Seed companies focus n producing commercial seed (seed for gardeners is a sideline in terms of volume and profit) and the emphasis has been on the ability to transport fruit long distances to satisfy the supermarkets. In doing this the flavour of many crops has diminished.

Gardeners and consumers crave the flavours we use to get. They want flavour rather than the ability to transport their tomatoes by air from foreign climes by air and road.

No problem.

Many of the varieties that our fathers and grandfathers grew are still available. Take tomato varieties for example. Commercially I grew Moneymaker ..and it lived up to its name. Local greengrocers wanted it as it sold better and these greengrocers were prepared to pay a premium for it. Admittedly the yields were very slightly lower .. but the premium I was paid more than made up for it.

Varieties such as Moneymaker have been around a long time. It first became available in 1913. And it has survived as long as it has for a simple reason. It is a good variety. It has good disease resistance, gives a good yield, is reliable independent of many soil and weather conditions and has great flavour. It’s also open pollinated which means we can save our own seed and can be grown indoors (under glass or plastic) or outside.

So the question we have to ask is why should we grow grafted plants when we have such good heritage plants? And it’s not just moneymaker tomatoes I’m talking about here. It’s all the other crops I mention above.

In most cases, I can’t see a single reason for a gardener to use grafted plants except in very special circumstances.

“Grafted Vegetable Plants Worked For Me”

I often hear gardeners say they have used grafted plants and they worked for them.

That’s good. But what does it mean? If we compare a reasonable crop from a grafted plant against a poor crop from a non grafted plant then it’s not comparing like with like. To be sure it’s better I want to see carefully controlled experiments that give well-evidenced results.

It’s really easy to let our enthusiasm carry us away with confirmation bias and convince ourselves that we didn’t buy an expensive plant that was no better than the lower cost one we grew a previous year.

We owe it to ourselves to be objective with experiments and not just produce a biased opinion with little firm evidence except our memory.

To me using Grafted Vegetable Plants is one of the Common Gardening Mistakes that new gardeners often make

Grafted Vegetable and Fruit Plants: Types of Graft

There are numerous types of graft that can be employed. The selection will largely depend on the type of plant being grafted.

Choices include Side Veneer Graft, Bark Graft, Splice Graft, Saddle Graft, Whip and Tongue Graft, bridge Graft and Inarch Graft to name but a few.

Learn More With These Grafting Books

To learn more about grafting I’ve brought together a range of books just on grafting.

Why not visit the Grafting Books page at The Gardening Guy Bookshop.

Common Grafting Questions