Some of the most commonly used aromatic herbs in a garden come from the Mediterranean. Thyme, basil, and oregano are excellent additions to marinades, sauces, and even medicinal teas. But rosemary might be the best known of these. This summer-loving perennial has so much use in cooking and in the pharmacy, but what if you don't have enough space to grow outdoors? You may have grown rosemary in your garden in the spring and summer and need to switch to growing rosemary indoors for the winter.
Don't worry there. Rosemary's versatility in the home goes hand in hand with its ability to be grown in a variety of settings. Are you a person struggling with mobility? Do you live in an apartment you might want to try growing rosemary year round, but you live in far north North America in a zone where the arctic winters turn off every living thing. Try growing rosemary inside!
Rosemary plants have a reputation for getting quite large in certain USDA hardiness zones, but that doesn't mean the right conditions can't be created to contain them. With the help of grow lights, a grow tent or a hydroponic system, you can get fresh herbs for cooking, tea, medicines or just flavorings at any time of the year – spring, summer, autumn and even winter.
Methods of growing rosemary indoors
Try growing rosemary indoors for easy access to the aromatic leaves. Source: Akirikku
Rosemary plants will grow in any type of indoor grow, as long as the right conditions are met. A large pot in a well-lit window with a good soil will house a healthy plant. Keep the plant in your kitchen or bedroom for easy access to enjoy the laid-back lemon scent while you relax. A potted rosemary plant in a south-facing window is not difficult to care for. Growing indoors also means the likelihood of pests is less.
If your home isn't getting enough sun to house a rosemary potted plant, grow lights can help. Each type of grow light offers a different condition. For rosemary, a sun-loving herb, fluorescent light is best. Find and furnish a spot in your home that suits your potted plant and light. You may be hanging out in this area a lot. Any area large enough for your potted plant will most likely also fit a small grow light.
Tents are another option for rosemary and can even be better than lights as rosemary prefers high humidity. A grow tent will keep light and moisture in, giving you conditions that mimick Rosemary's favorite place: the Mediterranean coast. The reflective interior of the tent allows light and moisture to bounce around inside. There are different types of tents, but they all take up a little more space than just a potted plant and grow light. If you have a lot of storage space with little overhang, a full-fledged tent construction could be the indoor rosemary solution for you.
Although woody perennials like rosemary plants are prone to root rot in environments with too much moisture, hydroponics is another option that allows you to harvest these herbs with great effectiveness. There are many different types of hydroponic systems, but a full set-up that uses nutrient sheet technology is best. The only downside to a hydroponic system is the space it takes up (at least a few feet wide and high).
Care for indoor rosemary
A healthy rosemary plant is green and lush. Source: issyeyre
So what are the requirements for growing rosemary indoors in each of the above settings? Follow these tips to learn more about the essential conditions for growing rosemary plants.
Lighting & temperature
Rosemary plants love a full sun zone or 6 hours of sunlight or more per day. For pot rosemary growing in a window, make sure you have access to the full spectrum of available sunlight. For people in the northern hemisphere, a south-facing window is best. The opposite is true for those in the southern hemisphere; A north-facing window is best in this regard.
Rotate the rosemary plant container or outside light for full sun coverage. Lights often come with a timer that allows you to set the amount of light per day. Start at six hours a day. If you find the plant is yellow or withered, shrink it down. If your rosemary plant looks stunted after just six hours, try scaling up from there. If you have a light without a timer setting, turn it on and off manually.
Room temperature (72 degrees Fahrenheit) is perfect for a rosemary plant that thrives in temperate coastal areas. A range from high heat to low 30's is also acceptable, although this is likely not something you will come across indoors. Rosemary is very hardy, but appreciates higher humidity. If possible, avoid the dry heat of an air conditioner. Water your plant more if you can't keep it away from a vent. Tents and hydroponic systems are great for maintaining the high humidity required for a rosemary plant to bloom.
Water & humidity
Rosemary needs good drainage and not a lot of water when the humidity is right. Water your rosemary plant indoors in a pot or planter regularly when the potting soil is dry. Less rosemary in winter. Like any flora, rosemary goes into dormancy during the colder months.
Rosemary is drought tolerant and doesn't require a lot of water to grow well. Let the soil dry out between waterings to avoid powdery mildew and other problems. Rosemary needs good air circulation, which helps prevent problems like powdery mildew that are common to rosemary, especially indoors.
For hydroponic systems, change the nutrient solution every three weeks. Some NFT systems come with small domes that you can place over the rosemary plant after it has been planted in the system for moisture control. Test the dome for a trial period and remove it if necessary. Humidity is easily maintained in tents and hydroponics. As long as there is enough water, rosemary plants absorb enough water to grow, and air circulation allows evaporation to drain away excess water that can damage the plant.
Growing medium & container
Eventually, a potted rosemary plant can even fill a large pot. Source: BellaEatsBooks
Since this plant prefers sandy, well-drained soils, you can pick up your rosemary in a soilless medium. Bottomless media are a combination of perlite, vermiculite and peat moss that simulate the coastal ecology of the Mediterranean. Rosemary roots don't need clay and prefer well-drained sandy soil to keep them alive.
A small container or pot is fine for propagation. But when it is time to transplant your rosemary plant, it will need at least 30 cm in depth to accommodate roots. Although rosemary prefers sandy soil, growing this plant in simple potting soil on a windowsill or under light is perfectly fine. A terracotta pot is great for rosemary as it draws moisture from the soil and prevents root rot. Plastic containers are also suitable, but the floor needs a lot of attention in this case as plastic pots retain moisture.
Plants grown indoors in a hydroponic setting need frequent checks to make sure the roots are healthy. As we'll cover in the Propagation section of this article, root rot hits rosemary quickly in water. If this happens, keep the water fresh and follow the guidelines that came with the system to prevent roots from rotting.
Self-watering pots usually contain too much water for rosemary plants. Since rosemary needs to dry out between waterings, plants grown in a self-watering container can cause root rot and powdery mildew. As long as the drainage is great, growing rosemary indoors is a sin.
Too much fertilization can damage rosemary. This herb doesn't need much more than good drainage and the right medium to stay alive. No fertilizer is required unless there is significant nutrient loss in yellowed leaves. In this case, a balanced liquid fertilizer with a full spectrum is fine. Change the nutrient solution in hydroponic systems every three weeks.
Rosemary likes to cut, like many aromatic herbs. Since this is a woody herb, trim the green tips of each branch to allow it to grow. You can do all of this at once or as needed. In spring and summer, more growth will come with pruning. In winter, when it is cold, reduce the cutting frequency. Prune the growth points right at the end of the new growth after the plant is established to encourage growth and keep the shape of the plant the way you want.
When your rosemary plant is growing flowers, kill them by the stem for greater herbal power.
Keep an eye on your rosemary leaves to measure plant growth. Source: BellaEatsBooks
To get rosemary from seeds, plant several seeds in a pot or starting container with a well-drained medium a few months before warm weather arrives. Although your goal is to grow indoors rather than outdoors, these plants have cycles that they can be felt in any location. Rosemary has a very low germination rate (around 30%), so sow several seeds at the same time. It also grows very slowly – many herbs take a very long time to ripen. So sowing in early winter is best. When the seedlings have matured to a height of 3 inches, transplant them into a larger container or into your hydroponic system.
It is easiest to propagate rosemary from cuttings. Just as you wouldn't leave the new green growth of a rosemary plant behind, use the same method to pick cuttings. A root hormone helps root development. Remove the lower leaves and dip the tips in the root hormone before planting them in either starting containers or the container where your ripe rosemary will live. You can plant several rooting rosemary starts in a container to create what is known as topiaries, in which you carefully shape the plant by wrapping it around other plants and pruning them as they grow.
Start hydroponic seeds in a growing medium like coconut or rock wool, and the transplant will begin with fresh water and nutrients into your system as the roots move through the medium. This takes about 1-2 weeks. When transplanting, place the seedlings about six inches apart to create enough space for frequent harvesting. Because the water flows in a hydroponic system and is clean, rosemary will not suffer from root rot as it would with traditional water spread.
Because rosemary is so hardy and likes dry conditions both outdoors and indoors, most of the problems are due to the soil staying wet for too long. It is not often that your rosemary plant becomes upset in arid conditions or even due to a lack of sunlight once it is established.
Powdery mildew can develop on needles if rosemary is watered from above. This powdery mildew looks like yellowish to white powder dust. To avoid powdery mildew, always pour water at the base of your plant. Overwatering can cause powdery mildew in the soil, or excess moisture retained in the media can give fungi and bacteria the conditions they need to multiply. A bit of fungus or mold in the soil is normal. But the result of too much water in the soil is root rot. Rosemary needs soil to dry out. If you keep it in a sunny or well-lit place, it shouldn't have a problem soaking up moisture in between waterings. If bacteria or fungi become a problem, remove the rosemary and transplant it into a dry medium in a sanitized pot.
Spider mites are an insect pest that occurs indoors on plants that have been introduced from outside. If you've decided to get your rosemary plant out of your garden for the winter, check for spider mites before moving them in. Spider mites weave a light web around needles. Take a close look at the internet before deciding whether or not to treat it with a commercially available insecticidal soap. If several small bugs crawl on the web, then it is spider mites. Always choose treatments that are safe for human contact when grown indoors. Applications may need to be submitted once a week for several weeks. Damaged branches should be removed and discarded.
Mushroom mosquitoes can hang on soil that is too wet. These are small fly-like insects, and while they won't hurt rosemary plants at first, they can reproduce in your growing medium and do more damage over time. For fungus mosquitoes, hang up a sticky trap or place a homemade trap in a small cup that is sealed with a plastic sheet with holes. Put things in the cup that mosquitoes like to eat, such as fruits or vegetables. Add a liquid solution of vinegar and dish soap. When mosquitoes eat vegetables or fruits, they fall into the solution and cannot leave the trap.
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