Recent Cold Weather Demonstrates The Effect of Temperature On Growing Plants. This Post Explains Plant’s Temperature, Light And Water Needs.

Understanding The Effect of Temperature On Growing Plants is vital if we are to grow good vegetable and fruit crops. And that basic understanding helps us to appreciate how other factors, such as light, nutrients, and water can impact a plant’s ability to grow.

All seeds have a preferred temperature at which they germinate and grow. For some it is relatively low and I often germinate seeds, in modules, in a cold greenhouse in winter. Other seeds, such as tomatoes, peppers, chillis, cucumbers, aubergine etc are warmth lovers and need higher temperatures to germinate quickly.

The Effect of Temperature On Growing Plants - seeds germinated in unheated greenhouse

But note I say quickly, because though they have preferred temperatures at which to germinate. They will germinate outside those temperatures. But NOT too far outside them.

So my winter sown lettuce, mizuna, Chinese cabbage, oriental mustards etc wil tolerate germinating at lower temperatures BUT take much longer to do so.

The books may say it takes, say, 5-7 days for a specific seed to germinate, but, if the temperature is lower, they could take a month or more.

And if we go too far outside the preferred temperature range the seeds could be killed or become dormant. If too hot the seed could cook rather than grow.

Temperature Doubts

Sometimes people doubt that seeds like tomatoes need warmth and point to the fact that they have self seeded toms growing in a greenhouse despite cold weather. The fact is they toms have germinated very slowly and prove my point that they can germinate outside the preferred temperature range, but have taken much longer. But they waited until the temperature wasn’t very cold ALL the time.

The Video Demonstrates Three Temperature Regimes

In the video we can see three batches of pre-soaked seed germinated at three temperatures. The one at ideal temperature has grown fast this the other two haven’t. It is likely tha the one that is to warm wil not germinate at all at that temperature but the cooler one will in time. It is just going to do do very slowly.

Watch the video and think about how temperature affects growing rates.

Then think about how light levels, nutrient levels and moisture will also affect growth rates. I talk more about that below.

The Effect of Light On Growing Plants

In the same way as temperature affects plant germination and growth so do light levels..

In a sense is is even more complicate. Seeds and plants don’t have eyes and it is easy to see light levels through our own eyes.

The thing is our eyes adapt to light levels. When it is very bright our pupils contract and let less light in. And if it is still too bright we screw our eyes up. And when the light levels are low our pupils expand, more light it let into our eyes and we see better.

Even though we know this we often think light levels are good for plants. A plant in a shaded area will be getting less light but when wee stand there our eyes adapt and we think it’s not too dull.

When it is dull the plant photosynthesises much slower and growth is affected. Over the last few weeks light levels have been poor on my garden and this, coupled with lower temperature, has resulted in lower growth rates. The thing is it is rare for just one of these factors to work alone. Often lower light levels mean lower temperatures.

One last thought about light levels. It’s not just how bright or dull it is. It is also about how many hours a day the plant gets light. Good light conditions for an hour a day isnt going to help a plan much. It needs at least six hours good light every day. And in winter, when in the UK temperatures are lower AND the days have few daylight hours, the plant suffers from both light levels and light duration.

The Light, Moisture, Temperature & Nutrient Rectangle

So far I’ve discussed how a combination of poor temperature and light can combine to create poor growing conditions. But the reality is that each of the above four factors can affect growth alone or in combination with the other factors.

And if you want to make life even more complicated there are plenty of other factors that can combine with these four to affect germination and growth rates. But more on that another day.

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Now For The Science Bit …. Supporting Research

Effect of Low-Temperature Stress on Plant Performance and Adaptation to Temperature Change

TY – CHAP
AU – Devi, Veena
AU – Sidhu, Amanpreet
AU – Avinash, Gosangi
AU – Sethi, Mehak
PY – 2023/04/06
SP –
N2 – Low-temperatures (LT) stress is one of the abiotic stresses in plants that affect cell survival, cell division, photosynthesis, and water transport, negatively affecting plant growth, and eventually constraining crop productivity. LT stress is categorized as, (i) chilling stress where low temperature (0–15°C) causes injury without ice crystal formation in plant tissues, and (ii) freezing stress (<0°C), where ice formation occurs within plant tissues. Both stresses are together termed low temperature or cold stress. In general, plants originating from tropical and subtropical regions are sensitive to LT, whereas temperate plants showed chilling tolerance to variable degrees. Low-temperature stress negatively impacts plants, may affect the survival rate of crop plants, and also affect various processes, including cell division, photosynthesis, plant growth, development, metabolism, and finally reduce the yield of crop plants, especially in the tropics and subtropics. To overcome stress generated by low-temperature exposure, plants trigger a cascade of events that enhance their tolerance by gene expression changes and activation of the ROS scavenging system, thus inducing biochemical and physiological modifications. In this chapter, a detailed discussion of different changes in plants and their tolerance mechanism is done to understand the plant’s response under LT stress.
T1 – Effect of Low-Temperature Stress on Plant Performance and Adaptation to Temperature Change
DO – 10.5772/intechopen.110168
ER –

Effect of Temperature (Cold and Hot) Stress on Medicinal Plants

TY – CHAP
AU – Srivastava, Kavita
AU – Singh, Sachidanand
AU – Singh, Anupam
AU – Jain, Tanvi
AU – Datta, Rahul
AU – Kohli, Abhidha
PY – 2023/01/10
SP – 153
EP – 168
N2 – Environmental factors such as light intensity, humidity, microbial attack, and temperature etc. are prominent in causing stress to medicinal plants which results in altered physiological processes. We know that medicinal properties in plants are attributed to the phytochemicals (secondary metabolites) present in them, which are governed by the various internal and external factors a plant is acted upon. One of the major factors that influence secondary metabolite production in plants is temperature under which a plant has to grow. Temperature extremes induce various physiological, morphological, and molecular changes in medicinal plants and these changes need to be addressed to find out approaches in order to empower medicinal plants’ growth and healthy survival. High temperature induces direct and indirect damage to plants via protein denaturation and inactivation of chloroplast enzymes respectively. Cold temperature stress induces reduction in water uptake by plants, thus leading to cellular dehydration. Thus, there is a need to develop suitable engineered medicinal species of plants by creating desired genetic modifications for optimum growth, survival, and productivity.KeywordsHerbal plantsMetabolic phenomenaExtreme temperatureAbiotic stressPlant response
SN – 978-981-19-5610-2
T1 – Effect of Temperature (Cold and Hot) Stress on Medicinal Plants
DO – 10.1007/978-981-19-5611-9_5
ER –

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