Watering is the most time consuming task of growing in greenhouse. In my opinion, watering is probably the most difficult skill to learn. Watering should never be a routine task, so forget about watering every Sunday morning. The timing and how much water plants need depends on many factors.
These factors are type of the plant, season of the year, temperature and air humidity. Also, if you are growing in containers, the size and type of them matters. The same applies to growing directly in the ground or raised beds. You should keep in mind the type of growing medium.
When to water plants in greenhouse?
If you are growing plants in pots in a greenhouse, tapping the pot is useless. Also, measuring water loss by estimating the weight of each pots is time consuming. The simplest way to find out when to water plants in a greenhouse is to look at the surface. If the soil is dry and powdery all over, water the plants.
Moreover, inserting your forefinger into the soil to the full depth of the fingernail will help to know when to water plants. If the fingertip remains dry, greenhouse plants need water. Check the soil weekly in winter and more often in summer – every day. How often you need to water plants depends on the weather too.
On a sunny summer day you might need to water plants twice a day. In winter plants may require water once every two weeks. Keep in mind that dormant plants need hardly any water during winter months. That is especially important for succulents.
What is the best time to water a greenhouse?
The best time to water plants in a greenhouse is in the morning, especially in cool weather. Don’t water plants in the afternoon when the sun is shining brightly as it will evaporate the water before plants can absorb it. However, in spring you might need to be watering plants any time of the day if the soil is dry.
Remember that roots need air as well as water, so soil should be moist but never soggy. Nevertheless, some flowering plants like Panicled Hydrangea and Calla Lily like to have moist soil at all times. However, most ornamental plants need a period of drying out between waterings.
What water to use for plants in greenhouse?
Although tap water is suitable for nearly all plants, you need to leave it to stand overnight to use for delicate plant types. It is very important not to use hard water on lime hating plants like Azalea, Orchids, Cyclamen and Hydrangea.
Rainwater is the best option as long as it is clean and not stagnant. Read more about the benefits on rainwater here. You can collect rainwater from the greenhouse structure. Just build a simple guttering system and attach the pipe which links to a water barrel.
How to water plants in a greenhouse:
For a hobby greenhouse a watering can and hose pipe are the most common watering methods. However, there are a few automatic watering systems which can make this task easier. Let’s find out how to water plants with a watering can.
Insert the spout under the leaves and pour water steadily but gently. Fill the space to the top of the pot and leave to drain completely. Watering with watering can is ideal to meet needs of individual plants. A 1 gallon watering can is enough for a small collection of plants. Make sure that spout is long enough. It is also handy to have an extension spout.
Remember that you need to use spout for watering established plants and not for seedlings or sown seeds. For them you need to use a rose nozzle. If you have a bigger greenhouse structure, hose pipe can be suitable for you. Here is a guide on how to water plants with hose pipe:
Connect a lance with an on-off trigger at the end of the hose. Insert the lance in the pot under the leaves. Use a gentle trickle, so you don’t need to turn the water full on. Using a lance helps to reach pots and trays at the back of the staging. Also, you can attach different spray heads. For example, you can use a fine and gentle spray for seedlings and seeds.
What is the most reliable method of watering greenhouse plants?
Drip watering is the most reliable method to water plants in a greenhouse. Each plant in a pot receives the same amount of water through a thin tube which is attached to a main pipe.
This system is automatic and comes with timer which controls the intervals between waterings. You can find more information on various automated irrigation greenhouse systems in this post.
How to water plants in greenhouse when on holiday?
Some plants can last long without water, for example cacti and other succulents, however, the majority need weekly or even daily care. If you are growing plants in ground in a greenhouse, use water bottle drip system when on holiday.
- Make a few holes at the bottom and on the sides of a 1.5-2 l plastic water bottle;
- Damp the soil completely;
- Bury the plastic water bottle into the soil next to the plants;
- Leave the mouth of the bottle open;
- Before you are about to leave on a holiday, fill the water bottle with water and it will gradually drip into the soil.
It is very important to damp the soil first. If it is too dry, it will just soak up all the water from the bottle right away. When the soil is damp, it will absorb the water by osmosis and deliver it to the plant roots. Soil will continue to absorb water from the bottle until it is evenly moist.
