An armful of zinnias are the epitome of the summer. These cheerful blossoms, which come in a vibrant spectrum of colors, are a must-grow for any flower enthusiast.
Since they are among the simplest cut flowers to raise, they make an excellent first crop for new growers and are a consistent, prolific performer for the majority of flower farms and gardeners.
Since the beginning, we’ve grown zinnias, and each year, I fall more and more in love with them.
Because they dislike the cold, zinnias prefer to be planted once it has warmed up a little. However, in chilly Washington, we start our plants in 72-cell trays in the greenhouse 4 to 6 weeks before our last spring frost. Many gardeners in warmer regions of the world are successful at direct seeding their zinnias out into the field.
Around the middle of May, after the weather has sufficiently warmed up and any threat of frost has passed, plants are tucked into the field. On our farm, we work to give each blossom the greatest possible start. Find out more about preparing the soil here.
After preparing the planting beds, we install four drip irrigation lines that are spaced about a foot (30.5 cm) apart, and we then cover the beds with a layer of pre-burned landscape cloth to keep weeds at bay. With five rows per bed, plants are spaced 9 inches (23 cm) apart.
Plants can grow enormously large and require some sort of support if given suitable soil and a consistent supply of water. We employ a layer of horizontally stretched Hortonova netting that is 12 inches (30.5 cm) above the surface. Metal hoops that we bent using our Johnny’s Quick Hoops Bender are used to hold the netting in place. Any stake, whether made of wood or metal, will do. As the plants develop, they push through the netting grid and receive the support they require.
Because they prefer the heat, zinnias must be grown in full sunlight. I always grow them in cloth for the extra heat in addition to choose a sunny location.
Since they are cultivated in such rich soil, there hasn’t been a problem with disease, which I was concerned about when we first started planting zinnias this close together. Every two to three weeks, we succession sow zinnias to provide a constant supply of these lovely blossoms throughout the summer.
Pinching your zinnias when they are young is the key to getting the longest stems from them. Here is how to accomplish it: Use sharp pruners to remove the top 3 to 4 inches (8 to 10 cm) of the plant when it is between 8 and 12 inches (20 and 30 cm) tall, right above a set of leaves. This instructs the plant to grow more stems above the point of the cut, increasing both bloom production and stem length. The image up top shows pinching with a different kind of plant.
Deadhead any spent blooms if you don’t routinely pick your zinnias in order to direct the plant’s energy toward growing new blossoms rather than setting seed.
Zinnias must be selected when they are completely ripe in order to stay fresh in the vase. Use the to determine if a zinnia is ready to be harvested “Waggling test Just gently shake the stem while holding it approximately 8 inches (20 cm) down from the blossom head. The stem is not ready to be cut if it droops or bends. It is time to harvest if the stem is rigid and continues to stand upright.
Zinnias are regarded as a “Adding a few drops of bleach to their water will help clean up soiled flowers. Given that the flowers are quite sensitive to cold, do not place them in the cooler.
There are an astonishing variety of zinnias available in every imaginable size, color, and shape. Whatever your requirements, there is undoubtedly a zinnia for you.
Consider how many options there are if you’re looking for flowers in the peach-salmon color spectrum, for instance.
Giant Salmon Rose, Cinderella Peach, and Queen Lime Orange are in the top row, from left to right.
sowing zinnia seeds
Because zinnias are known for hating root disturbance, it is better to direct seed into finely tilthed, easily draining soil. If you want to sit outside in the evenings, wait until May or June to do this. It’s still too cold if the evenings are cool enough to make you want to eat dinner indoors rather than outside. Your zinnias should be planted in a greenhouse or polytunnel if you reside in a region of the country where eating outside only happens once every five years.
Choose a sunny area, scatter two or three seeds there, 5 cm (2 in) apart, and space each cluster about 30 cm (12 in) away. When the seedlings appear, thin them out until there is roughly one plant every 12 inches (30 cm). Pinch the tips out to promote branching. Individual stakes work best for supporting zinnia plants. Use pea or jute netting to cover your young plants and support it between bamboo or hazel canes if you’re growing them in a vegetable or cutting garden for picking. The zinnias are barely supported and will climb up and through the grid. The netting will soon be covered in fresh leaves and foliage.
Staking them correctly is worth the work because they benefit immensely from early straight growth. They will never develop or bloom as effectively when supported vertically as they will if they collapse.
sowing zinnia seeds undercover
I use coir Jiffy pellets because zinnias detest root disturbance; this minimizes handling. In order for the seedlings to slip right out into their planting hole, you can also sow them into lengths of guttering.
When seeds are planted in modules or gutterpipes, there is no need to poke them out; the seedling can be put directly outside when it is still young and has only one or two genuine leaves. When it’s warm enough to sit outside at night, do this (usually June).
The seedlings should be planted in healthy, well-drained soil in a sunny location. As you plant them, pinch the tips to promote branching.
Stake each plant separately to promote healthy flowering and straight, tall growth.
growing zinnias in a pot
When the nights are warm in late May or early June, you can plant zinnia seedlings that you’ve purchased or grown yourself into containers (earlier if you keep the containers under glass for a few weeks). Before planting, wait until the seedlings have two or three sets of genuine leaves.
Choose your pot size wisely because different zinnia types require different sized containers. Put peat-free, freely draining compost inside. Plant no more than three seedlings in a pot with a diameter of 35 cm (1 foot), but this will actually depend on the variety you have, so read the instructions for each type.
4-6 weeks after planting, or around the time the fertiliser in the compost is depleted, water thoroughly and fertilize with a liquid fertilizer.
How deep should zinnias be cut?
I was apprehensive about cutting back my tiny Zinnia plants. Everyone advised cutting them back to help them branch out and produce more flowers, and after doing a lot of research and watching several videos on YouTube, I decided to follow their advice. I shuddered and removed them all. Let me tell you, cultivating zinnias was the best choice I ever made! They multiplied like weeds! I have enormous, overgrown plants that have simply continued to bloom all summer!
Zinnia plant pruning is quite simple. Simply wait until they are between 10 and 12 inches tall; you want to ensure that they have a few sets of leaves. You should remove the plant tops when they get to this stage. With a good pair of pruners, I removed the top two sets of leaves by about 4 inches. (See the image above) It’s that simple to prune zinnias!
Where should a plant be pinched?
A plant often emerges from the soil as a single stem bearing leaves when it first sprouts from a seed. This single stem formation will allow it to grow endlessly. While a plant will eventually start to enable new buds to form, growers can encourage bushiness in the early stages of the plant’s growth by easily trimming the plant’s tip off by hand.
Because it can hasten the development of full, luxuriant plants, pinching is desired. For the duration of the growing season, it is possible to maintain lush hanging baskets and flowerbeds on some plants, such as fuchsia. Yes, it will delay flowering, but in the end, the appearance is more lovely.
Pro Tip
Pinching must be done correctly, and older plants, woody shrubs, or trees should not be subjected to it. Topping is the term for when trees are “tipped,” and it can significantly harm your plant.
The term “pinching” is also used to describe the removal of young shoots to stop growth since it is done on fragile growth that is simple to remove by pinching the growth between our fingers.
Plants like tomatoes frequently develop extra side shoots and become bushier than desirable on their stems. Growers may decide to pinch out a few specific buds along the stem to limit this growth and lessen the amount of a jungle the plant develops. This may also motivate a tomato plant to focus its efforts on producing further fruit on the remaining stems.
Know where to pinch.
Your baby plant is prepared to be pinched once a few pairs of leaves have developed on a stalk. At the base of every leaf, right above the point where the leaf joins the stem, plants produce buds. We refer to this as a node. The internode is the stem that a plant has between each pair of leaves. Eliminate the growth just above the leaves to encourage these buds to open and create new branches.
Do not damage buds.
When pinching, you want to remove as much of the internode as you can, but you also don’t want to damage the delicate buds that are growing at the base of the leaves because if you do, they won’t grow properly once you’re done pinching. For this kind of precise, delicate pruning, use your fingernails or a little tool like a Fiskars micro-tip snips.
Repeat the pinching process when new leaves form.
The remaining buds will be encouraged to grow when you pinch your plant to remove the top growth. The remaining buds should start to open and generate new stems in a few days. These new stems will eventually produce new leaves with buds at their bases.
Repeating the pinching technique on these new stems once they have a few pairs of leaves will cause those branches to bush out even more. Avoid pinching branches below a point where you have already pinched while repeatedly pinching plants, nevertheless.
Flowering v. edible herbals
Pinching flowering plants will prevent blossoms from forming, so once your plant is sufficiently bushy, stop. Pinching is the ideal method for harvesting edible herbs like basil since it promotes new edible growth while discouraging blossoms and seeds. The development of flowers and seeds may impede the continued growth of the savory herbal leaves.
Pinching to discourage growth
Pick a tiny developing bud at the base of a leaf, and use your fingers or a pair of micro-tipped scissors to pinch it out. Even after these shoots have developed and started to grow, you can still remove them if you get behind on your pinching. Don’t remove all of a plant’s side shoots or it won’t branch out at all. Once gone, they typically won’t grow back.
After clipping, do zinnias bloom again?
The extreme heat and dry conditions have forced many growers to scramble to tend to and harvest their stressed fields and gardens, including here on our farm in the Skagit Valley and throughout much of the Western United States. While many flowers bloom profusely in this kind of weather, it is crucial to know the optimum times to harvest and ways to care for your fresh cut blooms immediately after they are cut if you want your flowers to last as long as possible—especially with the added stress of high temperatures. (This is referred to as “stage of harvest” and “post-harvest handling” in the language of flower farmers.)
Here are some of my favorite hints for avoiding heat waves and getting the longest vase life possible from 10 high summer flower varietals.
Zinnias: To ensure a long vase life, zinnias must be harvested at the proper time. Wait too long, and the blossoms will swiftly fade; harvest too soon, and the stalks will sag and droop. The “wiggle test” is a pretty easy way to determine whether your zinnias are ready for harvest. Simply take hold of the stalk a few inches below the flower and gently shake it. The stem will be delicate and flexible if it is young. When you wriggle the stem, it should stay rigid and straight if the plant is ready to be harvested. Cut time has come! To create a long, sturdy stem, deeply cut the plant. Don’t be hesitant to clip off lateral sprouts on the main stem you just plucked; remove the foliage as well. Because zinnias are “cut and come again” flowers, they will continue to grow all season long even after being severely pruned.
We cut zinnias and place them directly into clean, fresh water that has either been supplemented with a drop of chlorine or a CVBn pill. The little conditioning pills, which are frequently marketed for gerber daisies, are actually ideal for all of the “dirty flowers with hairy stems that easily gather dirt and bacteria that can muddy up the water.” The hottest time of the year is when zinnias blossom continuously, and they also enjoy heat throughout the post-harvest period. One of the few flowers we don’t treat in the cooler before delivery or design work is this one. Simply said, we keep them out of direct sunlight in a dark, shaded area of our studio. These few easy steps will give you gorgeous, long-lasting blossoms that last 7–10 days in a vase.
Note: In general, certified organic agriculture does not permit the use of commercial flower food. Using bleach or hot water and harvesting at the right stage are crucial if you have certification. To give your flowers the longest possible vase life even if you are not certified organic, CVBn tablets and other hydration and conditioning options are worth the extra money.
Basil: During the height of the summer, we nearly always add at least one or two stems of Cardinal, Oriental Breeze, Lemon, or Cinnamon basil in our mixed bouquets of flowers for grocery store clients. When the flower heads start to appear and the stems start to harden, I pick the basil. To keep them from wilting, I treat them with Quick Dip (a non-organic alternative) or boiling water (an organic alternative). As these plants wilt quickly, be cautious to harvest them in the cool of the morning or evening. Basil doesn’t like the cold, just like zinnias, so keep them out of the refrigerator to finish their conditioning. The vase is frequently where stems root, and they should last 7 to 10 days.
The fuzzy, aromatic leaves of scented geraniums are a must-have for bouquets, but if you don’t take a few simple precautions, they could wilt easily. In order to avoid the heat of the day, I always attempt to trim the scented geraniums first thing in the morning. I sliced them, placed them in cool water, and gave them 3–4 hours to rest and condition before arranging them. Dip the bottom 2-3 in boiling water for 5-7 seconds or dip the stems in Quick Dip if they are still wilting.
Another flower that is prone to wilting is the hydrangea. Perhaps more significant than the harvesting stage is how you hydrate the produce after it has been sliced. My secret is to cut them when they are still chilly, use Quick Dip quick hydration solution, or cut them into hot water for organic production. I am familiar with some flower growers who swear by dipping the just-cut stems in alum powder (found in the grocery store’s spice aisle), while others would soak the entire bloom in water before use to prevent wilting.
Cosmos: Cosmos generally don’t have a very long vase life, but if you cut them at the proper point, you can extend their beauty. Cosmos should be cut when just one petal is beginning to unfold, and once that happens, let the vase’s other buds and blossoms bloom.
Sunflowers: Harvesting the blooms just as the first few petals begin to lift off of the central disk and removing all but the top few leaves will give your sunflowers the longest vase life possible. This can be challenging for beginners since it still appears to be “closed” and not ready to pick, but if you cut them early, you can prevent bug damage and enjoy longer vase life. These people, who are referred to as “dirty flowers,” may benefit from some bleach in the water or from being cut into a pail of water that has been CVBn-treated.
Celosia: When harvesting crested celosias, also known as “cock’s comb,” wait until the crests are fully grown (or a bit sooner is good too), but before the plant begins to produce seeds. Before plucking celosias with feathers, let them stretch and become feathery. Make sure to remove around 3/4 of the leaves after cutting and submerge them in cool water.
Cerinthe: Harvest during the coldest part of the day, then immediately treat stems by putting the bottom 2-3 inches in boiling water for 7–10 seconds, followed by a cool water bath. After harvest, stems become extremely floppy, but once hydrated, Cerinthe can last up to a week in a vase.
Harvest rudbeckia when the flowers start to unfold. Black Eyed Susans are infamous for fast turning their water murky. By reducing this and extending their vase life, you can expect a vase life of 7 to 10 days by adding a few drops of bleach to the water.
If you have any more advice or methods for gathering high summer blossoms and extending their vase life, please let me know. Please share any more advice in the section below.