A Vegetable Growers Guide for Adapting to a Changing Climate

Climate zones are regions of the Earth that are classified on their long-term weather patterns, particularly temperature and precipitation. These zones help in understanding the diverse climatic conditions experienced in different parts of the world and are crucial for studying ecosystems, agriculture, and human activities.

Recognise that your local climate zone may be shifting due to global warming. Use updated UK Plant Hardiness Zone maps and consult local agricultural research data to identify the best planting times and crop varieties for your area. Adjust your planting schedule to accommodate longer or shorter growing seasons and be prepared to experiment and consider experimenting with new varieties that can withstand temperature fluctuations.

Climate zones are defined by the average minimum winter temperatures, and these zones are changing due to global warming. Gardeners should keep abreast of the latest updates to these zones and the growing seasons they indicate. Observing microclimates within your own garden—areas that may be warmer or cooler than the overall zone—can also provide clues on the best places to plant sensitive crops.

I remember my father, Ronnie, telling me about his childhood memories where winters were cold and summers were long and hot - every year! The first frosts were in September and it snowed occasionally in June.

He remembers the local market being held one winter on a frozen river Ouse in Bedford and it wasn't the only frozen river in winter, the Thames froze regularly. There was speed skating on Fenland drains and dykes and kids would play on frozen ponds and lakes. These may seem like extreme weather events, but the point is, the seasons were regular and predictable.

One of the biggest looming problems regards vernalisation. vernalisation is the process by which plants use a prolonged cold period naturally occurring during winter, to promote flowering and subsequent fruiting. One example is the floricane Blackberry which requires a number of 'cold-days' to initiate flowers. In the extreme, if this hedgerow favourite is not exposed to the required number of cold days, it will result in little or no fruit.

Things have changed radically in the past decades and we are now having to get used to milder winters and sometimes much warmer summers. The predictable weather patterns of years gone by are now well and truly a thing of the past.

Healthy soil is the foundation of a resilient garden. Regularly test your soil to ensure it has the right balance of nutrients and pH levels. Improve soil structure and fertility by incorporating organic matter such as compost and mulch. Practices like crop rotation and cover cropping can prevent soil depletion, enhance soil health, and reduce pest and disease risks.

Adding compost not only enriches the soil with nutrients but also increases its capacity to retain water and air, both of which are vital for plant roots. The addition of compost will also help to keep healthy populations of mycorrhizal fungi within the soil. This specific fungi type works symbiotically with plants to supply them with water and nutrients in return for carbon. It is worth noting, that this symbiotic relationship between plants and mycorrhizal fungi doesn't function for members of the brassica family (kale, cabbage, cauliflower etc).

Mulching with organic materials such as straw, leaves, or grass clippings helps regulate soil temperature, reduce water evaporation, and suppress weed growth. Cover crops, such as clover or legumes, can be planted during the off-season to protect and enrich the soil by fixing nitrogen and adding organic matter when they decompose.

• Compost: Enriches soil with nutrients and increases water and air retention capacity. It will optimise soil so mycorrhizal fungi can assist with water and nutrient uptake. 

• Mulch: Regulates soil temperature, reduces water evaporation, and suppresses weeds.

• Cover Crops: Protect and enrich soil during off-seasons, adding organic matter and fixing nitrogen.

You can read the GrowMad Guide to Cover Crops here.

GrowMad has a comprehensive list of seed suppliers here to assist with purchasing cover crops and green manure seed.

Efficient water use is crucial as water becomes increasingly scarce. Implement drip irrigation or soaker hoses to minimise water waste by delivering moisture directly to plant roots. Collect and store rainwater for irrigation using water butts. Mulching around plants can also help maintain consistent soil moisture levels by reducing evaporation.

Drip irrigation systems, which slowly release water directly to the base of plants, are highly efficient and reduce water loss through evaporation. Rainwater harvesting, involving the collection of runoff from roofs and other surfaces, provides an alternative water source that is both eco-friendly and cost-effective. Installing a simple rain barrel or a more complex system of tanks and piping can significantly reduce dependency on mains water supplies.

• Drip Irrigation: Delivers water slowly and directly to plant roots, reducing evaporation.

• Rainwater Harvesting: Collects runoff from roofs and other surfaces, providing an eco-friendly water source.

• Mulching: Helps retain soil moisture and reduce the need for frequent watering.

Creating microclimates within your garden can protect plants from extreme weather. Use shade cloths, row covers, and windbreaks to shield plants from excessive sun, wind, and frost. Planting trees or shrubs as natural barriers can also create a more stable environment for your vegetable garden.

Microclimates can be created using various techniques and materials. Shade cloths, available in different levels of shading, can be draped over plants to protect them from intense sunlight and reduce heat stress. Row covers, made from lightweight fabrics, can guard against frost and pests while allowing air and light to penetrate. Planting windbreaks such as hedges or rows of trees can reduce the impact of strong winds, which can dry out soil and damage plants.

• Shade Cloths: Protect plants from intense sunlight and reduce heat stress.

• Row Covers: Guard against frost and pests while allowing air and light to penetrate.

• Windbreaks: Reduce the impact of strong winds, which can dry out soil and damage plants.

The use of covered areas should be optimised too. Build a polytunnel or greenhouse if resources can be stretched, if not, use cloches, simple grow houses or cold frames. Any protected environment will benefit your production and extend cropping periods at each end of the growing season - earlier production in the spring and later harvesting in the autumn and early winter. Some crops can even be produced on a year-round basis.

Discover more about covered/protected cropping here:

Greenhouses

Polytunnels

Cloches

Cold frames and Grow houses

Climate change can alter pest populations and disease patterns. Implementing an Integrated Pest Management (IPM) approach can help manage these challenges sustainably. Use a combination of biological controls, such as beneficial insects, and cultural practices, like crop rotation and intercropping, to minimise pest and disease outbreaks without relying heavily on chemical pesticides.

IPM is a holistic approach that combines various strategies to control pests and diseases in an environmentally friendly manner. Beneficial insects, such as ladybirds and predatory wasps, can be introduced to control aphids and caterpillars. Cultural practices like crop rotation disrupt the life cycles of pests, while intercropping—growing different plants together—can confuse pests and reduce their numbers. Physical barriers, such as insect nets and traps, provide additional protection without harming the ecosystem.

• Biological Controls: Introduce beneficial insects like ladybirds to control aphids.

• Cultural Practices: Crop rotation and intercropping to disrupt pest life cycles.

• Physical Barriers: Insect nets and traps to protect plants.

You can find a list of useful Biological Pest suppliers and links here.

Diversify your garden with a variety of crops to increase resilience against climate impacts. A diverse garden is less likely to suffer complete loss from a single pest or weather event. Mix annuals and perennials, and plant different species and varieties to ensure a continuous harvest throughout the growing season

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Ensure that you plant early flowering subjects to provide a food source for bees that are emerging from hibernation earlier each year.

Diverse planting not only spreads risk but also promotes biodiversity, which is beneficial for the garden ecosystem. Companion planting, where certain plants are grown together to benefit each other, can enhance growth and deter pests. For instance, planting marigolds and basil alongside tomatoes can repel harmful insects. Including a mix of deep-rooted and shallow-rooted plants can also help utilise soil nutrients more efficiently.

• Companion Planting: Marigolds/tagetes and basil alongside tomatoes can assist in repelling insects.

• Varied Root Depths: Deep-rooted and shallow-rooted plants utilize soil nutrients more efficiently. Deep-rooted species will also assist in improving soil structure.

Adapt your gardening practices as conditions change. Stay informed about local weather forecasts and climate trends. Keep detailed records of your garden’s performance, noting any changes in weather patterns, pest issues, and crop successes or failures. Use this information to make informed decisions and adjust your strategies accordingly.

Gardening in a changing climate requires flexibility and a willingness to experiment. Detailed record-keeping can reveal patterns and insights that inform future planting decisions. Adjusting planting dates, trying new crop varieties, and modifying irrigation schedules based on current conditions can enhance garden resilience. Engaging with local gardening communities and extension services can also provide valuable support and knowledge.

When it comes to recording dates, I have a system of recording flowering dates for various ornamental plants and shrubs around the garden as an indication of whether the current season is ahead or behind previous years. eg the first daffodils used to flower during mid-March, these days, it's regularly mid-February for identical varieties. Our ceanothus always flowers around the 12th of May and the hydrangea 'Annabelle' flowers in a normal year on the 5th of July give or take a day. It's useful to compare these flowering dates as a yearly comparison.

• Record-Keeping: Track planting dates, weather patterns, and crop performance to inform future decisions.

• Community Engagement: Join local gardening communities and consult weather services such as The Met Office for support and knowledge.

If interested, you can discover more about labelling and record keeping with this GrowMad article.

Why buy brand new if you can reuse? We should all consider upcycling or recycling as part of our climate change strategy.

All products produced in a factory have contributed in some way to climate change at some point, even if it's only carbon emissions involved in their distribution. If they still function in some way, reuse them. Often, they will look better than brand new and more in keeping with an allotment surrounding.

Examples can include:

• IBC's for water storage. Find IBC's here.
• Old tyres for constructing planting areas
• Old timber for the construction of raised beds
• Old doors and windows for greenhouse or shed building

All of these materials are available from your local household recycling centre, reclamation yards, scrap merchants, tyre distributors or simply by trawling through social media such as Facebook Market Place.

Peat-free compost is a soil amendment made from organic materials like wood waste, coconut coir, and garden waste. It's become more popular in recent years due to concerns about the environmental impact of peat extraction, a non-renewable resource that stores much carbon. Peat-free compost can be lighter and have a more open structure than peat, and it may not have the same earthy smell. However, some high-quality peat-free composts can still produce a dark, rich colour

Peat-free gardening offers several environmental and practical advantages:

1. Environmental Preservation:

Biodiversity Conservation: Peat bogs are vital ecosystems that support unique flora and fauna. Extracting peat destroys these habitats.

Carbon Storage: Peatlands are significant carbon sinks, storing large amounts of carbon. Peat extraction releases this carbon into the atmosphere, contributing to climate change.

2. Sustainability: Peat is a non-renewable resource on a human timescale. Using peat-free alternatives promotes the use of renewable materials, which can be more sustainable over the long term.

3. Soil Health: Peat-free composts often contain a mix of organic materials, such as wood fibres, bark, coconut coir, and green compost, which can enhance soil structure and fertility by promoting microbial activity and improving water retention and drainage.

4. Water Management: Some peat-free materials, like coconut coir, have excellent water retention properties. They can help manage water more efficiently in gardens, reducing the need for frequent watering.

5. Local and Organic Alternatives: Peat-free options often use locally sourced, recycled, or organic materials, which can reduce the carbon footprint associated with transport and processing and promote the recycling of organic waste.

6. Legislative and Market Trends: Increasing awareness and regulation around peat use in many countries are leading to a greater availability and improvement in the quality of peat-free products, making them more accessible and effective for gardeners.

By opting for peat-free gardening, individuals can contribute to environmental conservation and adopt more sustainable gardening practices.

You can find a comprehensive list of Peat-Free Compost suppliers here.