Growing plants in ground has always been a traditional way for greenhouse gardeners. The two sides of the greenhouse floor are for planting vegetables like Tomatoes and there is a pathway in the middle. Most often people cover it with gravel or lay concrete slabs to walk on it and keep the pathway clean.
Today, you will find that many growers still plant crops directly in the ground while other keep potted plants in a greenhouse. In order to decide what methods work for you, consider factors like pests and diseases. However, not every plant can grow in containers. So, is it better growing plants in ground vs pots?
Do plants grow better in pots or in the ground?
Whether it is better to grow plants in pots or in the ground depends on the space and type of soil in your greenhouse. In terms of total yield there is no much difference between growing plants in ground vs pots.
The variety of the plant and growing practices are more important in the amount of crops produced. There are pros and cons of growing in pots and in ground, let’s have a look at each of them.
Pros of Growing Plants in Pots:
1. Pots come in different sizes and are made of various materials. Growing in pots essentially allows you to sow seeds, propagate cuttings or keep large decorative plants in pots.
There are different types of containers for plants:
- Clay pot – it is a traditional pot. It is less likely to topple over than plastic pot. Clay pots are porous so it is less likely to waterlog.
- Plastic pot – in comparison to clay pots, plastic ones are less likely to break if you drop them. Also, you need to water them less often.
- Wood tub – it is a large decorative container for shrub or collection of small plants. Wood planters are weather resistant and long lasting.
- Fiberglass planter – it’s main advantage is durability. Moreover, fiberglass planters are weather resistant, so will not splinter, crack or fade when exposed to the elements.
- Peat pot – it is a good option to start the seeds in before transferring plants to garden or bigger pot. The pot is bio-degradable. So, you can plant them directly into soil without disturbing the roots.
- Polythene sleeve pot – it is a very cheap and easy to store type of containers. Plastic sleeve pots are treated to resist UV rays and white color reflects light back to plants.
2. No risk of soil-borne diseases. Pathogens build-up in the soil and infect plants. You can avoid these problem by filling pots with soilless mixes. Use coir or peat based soilless compost.
3. Decorative options available. You can find pots made of clay, wood, fiberglass and plastic. They also come in different colors. So you can decorate the whole greenhouse in the same style. For example, clay pots give more a traditional and natural appearance.
Cons of Growing Plants In Pots:
1. Plants in pots require frequent watering. Pots, especially clay ones, dry out quickly. Pots don’t retain water for long periods of time. In comparison to growing in soil where plants can reach water in the ground. It is also due to higher surface-area-to-volume ratio.
2. Limited amount of plants can be grown in pots. Although you can keep some flowers and shrubs in pots, most flowering perennials and shrubs (Chrysanthemum, Camellia etc) need to grow in ground. As well as the vegetables and fruits (Tomato, Cucumber, Grape, Fig etc). Bigger plants have a wider root system so a container is not big enough.
3. Containers heat up and cool down faster. These fluctuations of temperatures are caused by the higher surface-area-to-volume ratio. It is because the size of the container is smaller that the ground. So when roots are in containers sudden changes in temperatures can slower the growth.
4. Constant addition of fertilizer. Due to the fact that most commercial potting mixes are based on coir or peat, these are low in nutrients. So you would need to add fertilizer to the pots quite frequently. It can also add up to your spending.
5. Topping up the pots. Organic plant fibers – coir and peat – break down over time. So, on average, you would need to top up the pots with potting media every year. Moreover, some plants you will not be able to repot and instead need to remove the top inch and add new mix.
Pros of Growing Greenhouse Plants in Ground
1. Less expensive. If the type of the native soil is loam, you can utilize it in a greenhouse. All you need to do is to mulch, tilt and water the ground. Add organic compost to increase drainage and you are ready to start growing. That way you save on store bought composts, potting mixes and amendments. Did I forget to mention that pots are quite expensive too?
2. Easier watering. Loam holds water and nutrients for longer in comparison to pots filled with potting mixes. It means that you need to go out less to water plants and it is less likely that you are going to overwater plants. Moreover, it is easier to install irrigation system on a flat surface.
3. No need to repot. Repotting can be a very time consuming task. Especially when you grow a lot of plants. That is why many growers start seeds directly in the ground. That way you skip transplanting plants from seed starting trays to 3 in pots, then to 5 in pots, 7 in and 10 in. Also, roots can be easily damaged when transplanting.
Cons of Growing Greenhouse Plants in Ground
1. Pest and diseases. Over the years soil becomes a host for diseases and pests. In a greenhouse that is a major drawback. Most greenhouse glazing panels filter out UV light which actually sterilizes soil naturally. Most fungal, bacterial and viral plant diseases are spread naturally by infected and contaminated soil seeds.
2. Low temperature of the soil. How may times you checked air temperature and are excited to start planting but then realize that soil is still too cold? First of all, many people forgot to test soil temperature before planting out. To heat the soil you would need to use heating cables which run on electricity. So, may growers find it more efficient to get a heated mat and keep the pots on it.
3. Soil becomes ‘crop sick’. When you grow the same plants in the same location year after year, soil gets sick. You will notice that the amount of fruit decreases and plants struggle from diseases. Sterilizing soil or changing it are both time consuming tasks and are not always efficient.
