Tip burn in hydroponic cilantro/coriander

An Essential Guide To Fix Tip Burns In Hydroponic Cilantro.

You transplanted a nice set of cilantro seedlings, and they have started to pick up. Their aroma fills your garden; you can’t wait to taste it. But before they reach their full size, you see the tips of the leaves turning brown. You leave it as it is, but then you see more tip burns in a week or so.

There are several reasons for tip burns in cilantro, significantly more so when grown hydroponically and indoors. This post discusses how to identify the root cause of the tip burn and which fix will work.

Tip burns at an early stage aren’t fatal to the plant. You can reverse them and make your cilantro green and lush again. Let’s dig in.

Nutrient burn

Nutrient burn isn’t the most common cause of tip burns, but it’s notable for hydroponic growers.

When there are too many salts in the nutrient solution, the plant absorbs them all with the water. Yet, that much salt isn’t healthy for the plant. Therefore, the plant’s natural mechanism is to push away as many salts as possible through evaporation. When the nutrient evaporates, it also takes a lot of water away. Therefore, certain areas of the cilantro leaves suffer from dehydration.

It’s easy to spot nutrient burn in hydroponic cilantro. Check the EC of the nutrient solution. If it’s more than 3, nutrient burn is probably why you’re observing this. For ideal growth, maintain the EC at around 2.

If you’ve concluded that nutrient burn is the cause of tip burns, you need to dilute the solution with pH-neutral water. Also, the water’s EC shouldn’t be more than 0.3. RO water is perfect, but check these parameters if you’re using tap water, rainwater, or well water.

Related: Water Quality in Hydroponic Systems: How to Ensure Your Plants Thrive

You should also be mindful of the hydroponic system when diluting. Kratky requires the suspended air roots to be maintained. Thus, you can’t add water directly to the container because it will cover the air roots. You need to mix nutrients separately and replace the container nutrients.

Insufficient Airflow

Air circulation is vital for any plant’s healthy growth. Cilantro is no different.

Airflow helps with transpiration. When air is circulated, water evaporates more easily from the leaf surfaces. When water evaporates faster, the plant’s nutrient uptake also improves. This is truer for minerals like calcium.

Plants show nutrient deficiency symptoms when there’s insufficient airflow and nutrient uptake. One such deficiency is tip burns, which are caused by calcium deficiency. Calcium is necessary to form cell membranes in plants. When it cannot reach the tips of the leaves, those parts turn brown and die.

Using fans to prevent tip burns in hydroponic cilantro/coriander

The fix for this kind of tip burn is easy. You must move your cilantro plant to an area with sufficient airflow. When moving is not possible, try having a fan. Industrial growers inside a greenhouse use fans to increase ventilation and avoid such problems.

The caveat is that we can’t fix the already burnt leaf tips. However, new leaves will grow and offset the damages.

Related: The surprising cause of tip burns in lettuce

Excess humidity

Once again, this is related to the same problem as before. Low airflow causes a lack of water evaporation, and high humidity also causes it. Water doesn’t get to the already moist air.

Thus, if you’re using a misting technique or something similar, you should stop using it. Humidity is contained in a closed environment such as a greenhouse. Even with fans, the humidity is usually high. This is because the plant’s natural transpiration process will increase the moisture in the air, which discourages the transpiration process.

You should use a dehumidifier to reduce the moisture in the air.

Nutrient deficiency

As mentioned, Calcium is a primary cause of tip burns. Boron deficiency also causes tip burns.

However, this is rarely the case in hydroponics. Often, we mix calcium nitrate to the NPK+micronutrient solution. Thus, there should be sufficient Calcium for the uptake. Also, the small amount of boron in the nutrient mix is sufficient for most leafy greens and herbs.

However, in hydroponics, the low nutrient concentration may cause nutrient deficiency. You may see tip burns in such instances because one of these two nutrients is not up to the level. If you’ve got an outdoor hydroponic system, the concentration may drop often after a rainy day.

In summary,

Tip burns happen for various reasons in cilantro. However, the significant reasons are predominantly hydroponics, high nutrient solution concentration, high air humidity, lack of airflow, and calcium and boron deficiency.

The fix for all these problems is straightforward and requires little effort and cost.

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