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Balcony gardeners cultivate hollyhocks in tubs in order to enjoy the romantic blossom magic far away from beds and farm gardens. For ambitious plant lovers, it is a matter of honor to raise the opulent summer flowers with your own hands. Important framework conditions must be observed so that the cultivation of hollyhocks in pots becomes a successful horticultural project. The decisive criteria are the best time, perfect tools and accessories, ideal germination temperature, optimal location and careful care. These instructions explain in practice how to sow and grow Alcea rosea behind glass in an exemplary manner.

Keep hollyhocks in a bucket

Best time

The ideal window for sowing opens in late summer and stays open until February. Choosing this date guarantees that majestic hollyhocks in magnificent blooms will be in the spotlight at the beginning of the next season in the tub. As a biennial perennial, the picturesque mallow plants only form a rosette of leaves as a floral foundation in the first year. In the second year, a strong stalk with the longed-for flower cups rises from it. Starting in the pot later, starting in March/April, can therefore delay the first flowering period until next year's season.

tip: Sowing Alcea rosea seeds in spring pots noticeably reduces the failure rate. A hollyhock that has been brought forward is put into the bucket together with the protective spring pot so that the sensitive taproot is not affected.

tools and accessories

Certified seed from the specialist trade leaves no doubt about the subsequent flowering result. Alternatively, just ask your home gardener friends about ripe capsules that form from the withered flowers of a hollyhock. Each capsule contains numerous seeds with a manageable size of up to 8 millimeters. Of course, it remains a secret until the beginning of the flowering period in which color and flower shape your preferred Alcea rosea will appear. However, there is no guesswork about the right tools and accessories for skilful cultivation:

  • Potting soil (ideally coconut fiber substrate or peat-free seed soil)
  • small pots with a diameter of at least 9 cm and an opening in the bottom
  • Shards of pottery, grit or expanded clay balls
  • Covering material (transparent film and household rubber or glass plates)
  • Watering can with spray attachment
  • Mini pike set (miniature prick stick, shovel and rake)
  • self-adhesive labels, pen

Meticulous cleanliness is the key to a magnificent result. Please clean all tools carefully with hot water and soap. If you use potting soil with humic components, we recommend disinfecting it in the oven. Fill the substrate in a fireproof bowl, spray it with water and put a lid on loosely. With 80 to 120 degrees top and bottom heat, all pathogens that could be hiding in the ground are destroyed within 30 minutes. Coconut fiber substrate is naturally germ-free, so this step is unnecessary.

Sowing Instructions

Place seeds and working materials on a table within easy reach. An old ceiling acts as a dirt trap. Gloves are not mandatory because hollyhocks and their seeds are not poisonous. At the beginning, please put a drainage in each pot to protect against waterlogging. A shard of pottery over the bottom opening is enough to allow excess irrigation water to drain off easily. Alternatively, spread out a thin layer of fine-grain grit or expanded clay pebbles. How to proceed:

  • Fill each pot two thirds to three quarters with potting soil
  • Moisten the substrate thoroughly with a fine spray of soft, well-settled water
  • Use a pricking stick to make a 1 cm deep seed hole in the middle of the substrate
  • ideally make two seed holes in each pot, 5 cm apart
  • Place seeds in a seed well, cover with moist soil and press down
  • Pull the cling film or foil bag over the edge of the pot and fix with household rubber
  • Attach a label to each pot with the name of the plant and the date of sowing

The seeds of Alcea rosea are dark germs, so a 1 to 1.5 cm thick substrate layer is important for smooth germination. Lightly pressing the soil ensures a good ground contact. The transparent cover also plays a key role. A local, warm, humid microclimate is formed, which helps the hollyhock seeds to germinate. We recommend a foil bag as an ideal hood for growing fast-growing hollyhocks in the tub. In contrast to transparent film or glass plates, a plastic bag can grow with you, at least in the initial phase. Foil or glass plate must soften early to avoid contact with the cotyledons.

location and germination temperature

A bright location that is not in full sun offers ideal conditions for seeds and seedlings. Although Alcea rosea is a sun worshiper, direct sunlight will cause young plants to languish before a full root system has developed. Pleasant temperatures of 20 °C to 22 °C guarantee rapid germination within 14 to 21 days. If the thermometer falls below 18 °C, you will look in vain for the cotyledons.

Caring for hollyhocks in the tub

Air the cover on each nursery pot daily to prevent mold from forming. Take this opportunity to check the moisture content in the substrate. To do this, press your finger a few millimeters into the ground. If you don't feel any moisture, spray the substrate with soft, room-warm water. Fertilizers are not given to young hollyhocks at this stage of growth. The poorer the soil, the more your pupils strive for a strong root system. If at least three pairs of leaves have formed above the cotyledons, a first dose of diluted liquid fertilizer will stimulate growth. From this point on, please place a supporting stick next to each hollyhock.

notice: If you prefer hollyhocks behind glass, an acclimatization phase begins in early May. Therefore, place the potted plants outside in a semi-shady, warm location during the day. Until the middle/end of May, put the flowers away in the evening to avoid the risk of delayed ground frost.


The longer a young hollyhock can stay in the seed pot, the easier it is to move to the bucket. If a seedling has fully rooted its pot and the first root strands are even peeking out of the bottom opening, then the last step of cultivation is on the agenda. Please choose a bucket with a diameter of 40 centimeters and an opening in the bottom for water drainage. A peat-free, nutrient-rich and well-drained pot plant soil sets the course for vital, flowering growth. How to do it right:

  • create a 5-10 cm high drainage in the bucket
  • Fill in the substrate up to a pouring edge of 5 cm
  • Dig out a planting hole by hand or with a shovel
  • Stick the support stick into the ground next to the trough
  • Repot the hollyhock and plant in the middle
  • pour thoroughly until the first drops run out of the bottom opening

It is important to note that the previous planting depth of your young hollyhock remains unchanged. Therefore, please pay special attention to the taproots when repotting and repotting. Root strands should not be kinked or damaged in any other way. The nutrient reserves in the substrate cover the needs for about four weeks. Hollyhocks in the tub then benefit from a rich liquid fertilizer that you add to the irrigation water at intervals of 10 to 14 days.

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