Growing food

Growing Conditions For Lemongrass (Sun, Soil, Water)

Lemongrass is a great perennial herb for people who live in areas without cold winters as it loves the sun and the warmth. For those in colder regions, this flavorsome herb can easily be grown indoors.

Lemongrass needs 6+ hours of sun daily. Plant it in well-draining soil with a pH between 5 to 8. Lemongrass prefers a temperature range between 50 to 91 degrees Fahrenheit (10 to 33 degrees Celsius), so it can be grown in USDA zones 9 to 12. It also likes to be kept moist and should be spaced 2 feet apart.

Here’s a comprehensive rundown of the ideal growing conditions for lemongrass.

Does Lemongrass Need Full Sun?

Ideally, your lemongrass should receive around 6 hours of sunlight daily. The plant uses the sunlight for photosynthesis to feed plant. The more sunlight your lemongrass gets, the more flavorsome it will be. This is because the sunlight helps the plant to produce more of the oils that produce the lovely lemony flavor and fragrance.

Growing your lemongrass in a nice sunny spot also means that it will grow much faster and produce more of the fat stems that so many people like to use in their Asian cooking. If your plant does not receive enough sunlight, then it might reduce the growth rate, and you’ll get thinner, grassy blades rather than lovely fat stalks.

Planting your lemongrass near a structure that reflects the sunlight is ideal as this keeps the plant nice and warm and allows it to thrive. Therefore, if you can find a nice sunny spot near a brick wall or a fence, your lemongrass will reward you with lots of healthy growth.

In saying that, it is possible to grow some lemongrass in a semi-shaded position if you don’t have a sunny spot in your garden. What you’ll find is that your lemongrass won’t grow as lush or as fast, and the flavor will be a little milder because the plant has not been able to create as much oil.

Another way to give your lemongrass the amount of sunlight that it needs is to grow it in a large pot. When you do this, you can easily move the plant around during the day to follow the sun. This will ensure that your lemongrass gets all the sunlight that it needs.

If you are planning to grow lemongrass indoors, make sure that you place it in front of the brightest window so that it gets as much light as possible. You might also like to invest in a grow light for your lemongrass. This will not only provide the light that your plant needs but also enough warmth to keep it growing happily.

The Best Soil For Lemongrass

When it comes to soils, lemongrass is fairly forgiving and will grow in a variety of different soils. However, if you want to grow the best lemongrass in your neighborhood, you should plant it in rich, loamy soil that has had plenty of organic matter added. The soil pH should ideally be between 6.5 to 7. This range includes slightly acidic to neutral soils.

If you can prepare your soil well before planting your lemongrass, you’ll have the most success with your plants. To do this, first, check the pH of your soil. You can do this either by purchasing a pH testing kit from your nearest garden supply store or by sending a sample of soil off to a testing laboratory in your area.

Once you get the results, you’ll know whether your soil is acidic, alkaline, or neutral. A soil pH less than 6.5 is considered acidic and less than 5.5, strongly acidic. A soil pH over 7.5 is considered alkaline. Soils with a pH of between 6.5 to 7.5 are considered neutral.

The reason that the soil pH is important is that at certain pH levels, the nutrients in the soil are not readily available to certain plants, and these plants will then suffer from nutrient deficiencies. However, as stated, Lemongrass can grow quite happily in a wide range of soil pH, so it should not be necessary for you to amend the soil in most cases.

In general, adding plenty of matured compost and other organic matter should help to get your soil to a desirable state for growing lemongrass. This should also help to improve the drainage in heavier soils and give very sandy soil a little more moisture-holding ability. You see, the ultimate goal is to have soil that retains some moisture but does not become waterlogged.

You can also add some well-rotted animal manures or composted seaweed to the soil. This is especially useful if you want to increase the acidity of your soil. The other benefit is that this will feed your new plants as they’re growing.

Lemongrass Spacing

A lemongrass plant does require enough space so that it can grow to its full potential and produce more of those lovely flavorsome stalks. A mature plant can reach a height of three to five feet and a width of around two feet.

The growth of lemongrass is similar to other clumping grasses in that it will spread in order to produce many more stems.

Therefore, you need to ensure that you give your lemongrass plenty of room to spread when you first plant it. Ideally, you want to space your plants 2 feet (24 inches or 60cm) apart. This will ensure that the plants can grow to their full potential and won’t be overcrowded.

If you’re growing your lemongrass in rows and want to plant out multiple rows, then you should space the rows around 3 feet (90cm) apart. This essentially gives you enough room to walk in between each row for when you want to feed, maintain or harvest your lemongrass.

If you plant your lemongrass closer than the recommended spacing, you’ll find that you’re going to have to lift and divide your plants much sooner to ensure that they have room to spread. Bear in mind, too, that lemongrass roots can bulk up and spread. Therefore, if the plants are grown too close together, the roots will be competing for both nutrients and water.

The same goes for lemongrass that is grown in pots or containers. You should choose a large pot no smaller than 12 to 14 inches in diameter. Better still, consider growing lemongrass in large buckets. If the pot that you’re using is too small, you’ll find that the bulky roots will break through the sides and the bottom of the pot.

MokkieCC BY-SA 3.0, via Wikimedia Commons

However, having really large pots indoors is not always practical. So, what do you do? The solution is to plant in smaller pots and divide your plant often. You’ll find that lemongrass grown indoors will not grow as fast as the plants that are grown outdoors in full sun.

Therefore, if you choose a smaller 8 inch (20.5cm) pot for your lemongrass, you should only have to divide and repot it once a year.

In Which Hardiness Zones Can You Grow Lemongrass?

Lemongrass will grow as a perennial in USDA hardiness zones 9 to 12. This means that your lemongrass will continue to grow year after year. Here’s what to expect from your lemongrass depending on which zone you live in:

  • USDA hardiness zones 10 and above. Your lemongrass will slow its growth in winter, but it should still remain green. However, the plant may look a little bedraggled and could have some dead or brown leaves around the base. This is then the perfect time to do a little maintenance and trim away all those old leaves.
  • USDA hardiness zones 8b to 9. During winter, you’ll find that the leaves of your lemongrass will turn brown in response to the drop in temperature. What you need to do is remove the brown leaves and add a thick layer of hay or straw mulch over the plants or even a frost blanket. This will protect the roots and keep the soil temperature a little warmer. New growth will sprout as soon as the temperatures warm up again.

If you live in another zone that is colder, then your lemongrass will die once the temperature drops and you get the first frost. In this situation, you’re better off growing your lemongrass indoors.

Even if your lemongrass is growing in the ground currently, you can still save some of the plants and pot them up into containers to bring indoors. It’s just a matter of digging up a few clumps, dividing the plants, and then putting each one into its own pot.

Remember that lemongrass will go dormant in winter, so you don’t even have to turn on the grow light once you bring your plants indoors. Lemongrass will overwinter quite happily in your basement or garage as long as the temperature doesn’t drop below 50 degrees Fahrenheit (10 degrees Celsius).

Then, once any chance of frost is over, take your plant back outside and give them a good dose of sunshine and warmth. Once you see new growth, you can add some liquid fertilizer to help stimulate the plant even more.

Watering Lemongrass – How Much And How Often

As mentioned above, lemongrass does like a fair bit of moisture and also benefits from increased humidity. How often you water your lemongrass depends entirely on the climatic zone that you live in.

If you live in an area with high rainfall in summer, you may not need to supplement the water for your plants once they’ve become established and are actively growing. They should be able to get all the water that they need just from the rain. Plus, the constant summer rains will also ensure that there’s plenty of humidity in the air.

On the other hand, if you live in an arid region, you may have to water your lemongrass every second day to ensure that the soil does not stay dry for any length of time. In this type of climate, it’s also important to provide your plants with some misting, as this helps to increase the humidity.

Ideally, you would set up an irrigation system for your plants and use misting type sprinkler heads that replace the drippers that these systems normally use. If your plants are large, you’ll need at least one or two misters per plant.

For more temperate climates, it’s best to check the moisture level in the soil by sticking your finger into the ground up to the first knuckle. If the soil feels totally dry, then it’s time to water. On the other hand, if the soil is still quite moist, you can leave the watering and check again the following day. Alternatively, you can use a moisture meter if you don’t want to stick your finger into the soil.

It’s important to remember to never let the soil dry out completely if you want your lemongrass to continue to thrive. For this reason, the best time to water is in the late afternoon or the early morning.

Conversely, if you’re growing your lemongrass in a pot, you might have to water on a daily basis in summer. This is because the soil in a pot dries out much faster, especially when the plant is sitting in the sun. It’s also a good idea to cover the top of the soil with some mulch to cut down on evaporation.

Of course, it goes without saying that your pots should have adequate drainage holes because you don’t want the roots sitting in water continuously. For pot-grown plants, you might like to mist them regularly with a spray bottle filled with water during the hotter growing months.

The only time that you can slow down with the watering is over winter because, at this time, the plants will be dormant. During the colder months, your plants will only need around half the amount of water than they do over the strong growing season.

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