Due to unprecedented demand, we are temporarily unable to accept new product orders - but you can still become a member. Whilst we have good supply of products, our priority is to reduce the extensive delays on existing orders. When we re-open our online shop it will be to members only. Please stay safe, and keep checking back here as we will be back up to full service as soon as possible.  See the home page for further COVID-19 information and updates.

Due to unprecedented demand, we are temporarily unable to accept new product orders - but you can still become a member. Whilst we have good supply of products, our priority is to reduce the extensive delays on existing orders. When we re-open our online shop it will be to members only. Please stay safe, and keep checking back here as we will be back up to full service as soon as possible.  See the home page for further COVID-19 information and updates.

Tomato Growing Problems

Caromy MacDougall explains some common tomato growing problems and how to minimise them

Plant tomatoes 1m apart to reduce the risk of pests and diseases

The 2013 tomato taste tests at the Adelaide Botanic Garden brought out throngs of tomato connoisseurs, but among the tomato tips and chat about favourites was a reoccurring theme of poor yields and crop failure.

Yields from field grown tomatoes vary with season and region and, as we were experiencing a pretty good crop at Heronswood, we were left wondering what was occurring in South Australia, and if their problems were unique to the area. Although not everyone has the same problems as Adelaide we can use it as a case study to highlight how to diagnose problems in your own patch.

Jan, from our Adelaide Garden Shop, points to heat and low humidity as the culprits. Heat stresses tomatoes; they typically wilt as they struggle to balance water uptake with water loss during very hot days. However a less understood impact is that flowers drop and fruit set aborts when temperatures exceed the ideal growing range for extended periods (e.g. days above 29°C and nights above 21°C).

Humidity also plays a two part role. Tomatoes like 40-70% humidity, for although we tend to think of high humidity as bad (it facilitates the spread of moisture borne diseases such as fungi), it can also be problematic when it is too low.

Air moisture is required to help pollen stick to the stigma and to allow flowers to pollinate, while some major pests, such as two-spotted mites, thrive and become a serious problem in drier conditions. So climate and season play a significant role in vegetable production, but how does knowing this help you?

If you can identify the issues you are dealing with you may be able to either prevent or treat resulting problems.

♦ Observe your plants for symptoms and/or pathogens. Photos or notes may help ensure you remember exactly what you observed.

♦ Online searches or an Australian specific disease reference book will help identify most common issues. We've also provided some tips below. Think plant and soil, and consider diseases, nutrient levels and pests.

♦ Identify the conditions that support the problem.

Can you change these or do you treat the symptoms?

Set your garden up to minimise common problems

♦ Plant tomatoes a metre apart. This improves airflow and minimises physical transfer of pests and diseases between plants.

♦ Try not to grow tomatoes in the same soil each year. Rest beds for 3-4 years before replanting with tomatoes or bio-mustards can be used to reduce the presence of harmful microbial activity by fumigating the soil after a tomato crop.

♦ Prune on low humidity days to reduce fungal diseases in open wounds.

♦ Clean pruning tools between plants (hand sanitising lotion or methylated spirits will do the trick).

♦ Never compost diseased plant materials as this may spread pathogens around the garden.

♦ Mix up your plantings. Many pathogens are host specific (e.g. they only feed off one species or family of plants). Interspersing beds with other species can provide physical barriers or regions without food that can prevent or slow their spread.

♦ Use companion planting. Planting marigolds around tomatoes suppresses nematodes which damage tomato roots.

♦ Identify a few good varieties that are best suited to your area and grow them well, rather than expending your energy and resources on lots of poor yielding plants.

Tomato breeding often focuses on cultivars which withstand cooler temperatures (allowing for a longer productive life), however heirloom varieties do vary in tolerances, so if you know your region has a specific challenge you may be able to find something suited to your site.

By growing a range and collecting seeds from the healthiest and best yielding varieties in your own garden you can develop a seed bank suited to your specific conditions.

So, on reflection, the problems experienced in Adelaide were probably both seasonal and specific (although doubtless not unique) to the area.

In the long term we may need to collect seeds and breed varieties specific to our conditions (maybe we’ll end up with region specific Australian heirloom tomatoes) but for now, by understanding the problems we face, we can address them and still have successful crops in what can sometimes be a challenging climate.

Flowers can drop when temperatures exceed the ideal growing range

More

A year’s supply of vegetables for two in just 20m2

Ryan Garratt and Sam Hidalgo anticipate the huge yields at Heronswood this summer

Beyond organics… exploring harmonic agriculture

Luca Foglietti shares his personal philosophies on combining science and ancient wisdom in our organic seed production.

Choosing Beautiful, Edible Plants

Bernadette Brady talks about creating art with vegetables at Heronswood

Garden Pyramid

Clive Blazey explains the Diggers guide — our Garden Pyramid

Garden Recovery After A Bushfire

Where to start? What do you need to know? Join Sophie Thomson for all you need to know after the bushfire has passed.

Gardening with Flowers

Choosing the best Diggers selections for the cutting garden

Grow Your Own Berries

Tim Sansom gives his tips on pruning and training for success with your cane fruit crop

Grow Your Own Food (Early Summer)

Bernadette Brady helps you start growing your own food in just 1-3 weeks

Grow Your Own Organically

Bernadette Brady explains how we make 'weed tea', control pests and serve organic food in our restaurants

How to drought proof your garden

How to drought proof your garden

Maximising yield by summer pruning fruit trees

Julian Blackhirst explains the essentials to improve yields from your orchard.

Moon Planting

St Erth's head gardener Julian Blackhirst explains the lunar planting cycle

Plant Ratios for the Backyard

Clive Blazey's thoughts on providing the right balance of plants in your backyard

Q&A - Green Manures

Trials manager Ian Magnus answers questions about using green manures to boost soil fertility and water retention

Q&A - Mulch

Bill Bampton, head gardener at Heronswood, explains our success with making and using mulch

Q&A - Seeds

Seed manager Evette Jungwirth answers your questions about growing from seed successfully

Q&A - Soils

Hugh Hunkin answers your questions about soils and why they are at the root of most gardening problems

Soft green succulents for a lush green garden

Bill Bampton transforms Heronswood’s gravel garden

Spring Gardening

Bernadette Brady recommends getting your hands dirty with some tasks in the spring garden

Subtropical Growing Zone

Tim Sansom explains the heat generated by “Hot Zone” discussions

The “Hauteculture” of Espalier

Bill Bampton talks about turning an untidy orchard into a bountiful border

The best flower selections for ‘This goes with that’ summer borders

Clive Blazey, author of ‘The Complete Guide to the Flower Garden’, discusses the power of intelligent combination

Tips for keeping your plants healthy throughout the seasons

With air-conditioning becoming the norm in many homes across Australia, we asked indoor plant expert Jason Chongue to share his top tips to growing indoor plants in all seasons.

Veganics and plant-based living

Plant-based living launches Veganics The vegan movement is gathering momentum for many reasons from animal welfare to climate change, and this is creating a wave of change across all industries from wine, to clothing and even gardening.

Related Magazine

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