Frost can be a gardener’s nightmare, tomatoes are tender plants and they can be damaged by a light frost. In some cases frost-damaged tomato plants can be saved, but in other cases it is not worth it and you would be better off starting again.
The delicate balance of temperatures and weather patterns can make or break a growing season, with the potential for cold damage looming over plants, particularly in the spring and autumn months. In this comprehensive guide, we’ll explore the effects of frost on plants, how to recognize frost damage, and crucially, strategies to save frost-damaged plants and prevent future occurrences.
Understanding Frost Damage
Frost occurs when temperatures drop below freezing, causing ice crystals to form on plant surfaces. A light frost is one when the air temperature drops below freezing, but the soil stays above freezing. In a hard frost both air and soil freeze.
Frost is typically anticipated in the winter months, it becomes a problem when it comes late, which depending on your hardiness zone might be after late March/April time. Or if it comes early, say before the start of November.
The best way to anticipate an early frost or a late frost is to keep records year on year to know what dates you would expect. Obviously with our changing climate, I always expect the unexpected. But starting with an annual record for my area gives a good benchmark. Also keep a close eye on the weather forecast in the period when you might be hit with a cold snap when you have tender or new plants exposed. If cold temperatures are forecast then take action.
The other observation to make is if you have a frost pocket in your garden. Lower areas of the garden are where you will find a frost pocket. Frost flows down hill. Frost will get trapped in shady areas and behind walls and fences, creating frost pockets. A frost pocket is the area of your garden that will always get frost first and will likely stay frosted for the longest. Do not plant young tomato plants in the frost pocket, as they are at higher risk of suffering frost damage if you do get hit by a cold snap.
A light frost may only affect the outer layers of plant tissue, some tender plants can survive a light frost. While a hard frost can penetrate deeper, damaging cell walls and causing irreversible harm. Plants most at risk include tender vegetables, young plants, and those in exposed areas such as frost pockets.
Recognizing Frost Damage
Signs of frost damage vary depending on the severity of the frost and the type of plant affected. Common indicators include wilted or brown or blackened foliage, damaged leaves, and stunted growth. In severe cases, entire plants may appear lifeless, with dead parts evident throughout.
It is important to look closely at your tomato plants, because whilst it might look brown, wilted and full of damaged parts and you may think the plant is dead, this may not be the case. In fact there may be some green shoots or stems that have survived the frost. This is the start of saving your frost damaged tomato plants.
Also brown or wilted leaves are not a sign that all is lost. Simply remove the damaged leaves from the small area of the affected plant. If there are existing leaves already growing, the plant should be able to grow successfully from these.
Saving Frost-Damaged Plants
It’s always sad and disheartening to wake up to an unexpected frost and to go out and see the damage in the garden. There are steps you can take to salvage affected plants and encourage new growth.
1. Assess the extent of the damage – if there is nothing green left at all the plant you should replace the plant
2. Remove any dead or damaged parts to prevent further stress on the plant
3. Encourage new shoots by providing optimal growing conditions, such as moist soil and ample sunlight
4. Feed with a comfrey or nettle tea, this will give the damaged plants a boost of great nutrients to help with their growth
5. If you haven’t already, add a top layer of mulch around the plant, this both protects the soil from further damage by keeping it warm and it provides nutrients to the plant
Protection Against Frost
Prevention is key to minimizing the risk of frost damage. Utilize various methods of frost protection, such as row covers, plastic sheeting, or old sheets, to shield vulnerable plants from freezing temperatures. We have recently made a hoop house, which is a great way to protect young plants. Plastic tubing and cover materials are useful to erect a makeshift protection frame if and when cold weather is forecast.
Drape horticultural fleece gently over the growing plants, also you can use heavy fabric row covers or bubble wrap for added insulation, particularly during spells of cold weather.
Plants covered with with heavier materials should have their covers removed during the day as soon as the risk of frost has passed. This will allow the plants to receive ample sunlight to grow.
Timing and Forecasting
Stay informed about upcoming weather patterns and the likelihood of frost in your region. Keep track of the last frost date and take action if an unexpected cold snaps occur. Monitor weather forecasts regularly and be proactive in implementing frost protection measures to safeguard your plants.
Tips for Tomato Growers at the end of the season
At the end of the season tomatoes are particularly susceptible to frost damage, especially during the ripening process. There are two main things to do to protect them:
1. Protect green fruit and mature green tomatoes by harvesting them before the first frost hits.
2. Using containers or row covers to shield tomato plants from cold winds and frost pockets.
3. If the ripening fruit is affected by frost, harvest and eat what you can straight away. Frosted tomatoes will not store for long. As long as they are still red then you can eat them. If you are in doubt, use them for cooking.
4. As with young plants remove any damaged leaves or fruits and as long as the damage is minimal the plant should continue to grow as long as you continue to provide optimal growing conditions of mulch, moisture and sunlight.
Preventing Future Frost Damage
To mitigate the risk of frost damage in the future, select plant varieties suited to your climate and growing conditions. Some tomato varieties are cold hardy, in fact some tomato plants can survive the winter, usually by being brought inside to grow.
Choose warm-season crops for regions with cooler temperatures and consider planting in sheltered areas to avoid exposure to cold winds. Implement mulching techniques to insulate soil and regulate temperatures around plant roots.
Conclusion
Frost damage poses a significant threat to gardeners and growers. With careful planning and proactive measures, it is possible to mitigate its effects and protect vulnerable plants. By understanding the signs of frost damage, implementing effective frost protection strategies, and fostering optimal growing conditions, you can ensure a bountiful harvest and maintain your garden in good shape throughout the growing season. Keep up to date with weather forecasts and act swiftly to safeguard your plants from the risks of frost damage.
I would love to hear about how you have helped your plants to thrive after being hit by frost. Please share in the comments below.