How to Speed Up Growth - Grow Faster

In short: Plant forcing shortens the time from sowing to harvest or flowering by growing plants at higher temperatures. Plant bulbs in pots in September, root them in a cold frame, then harden them at 10 to 12 °C for about two weeks before moving them to 16 to 18 °C. Flowering follows 3 to 6 weeks after removal.

Plant forcing is a growing method that shortens the time from seed sowing to plant flowering or harvest. It is most commonly used for growing vegetables outside the normal growing season (cultivation in greenhouses, cold frames, or polytunnels), but it is also used for timing the flowering of ornamental plants. Among the most frequently forced flowers are tulips, daffodils, hyacinths, and other horticulturally attractive bulbs.

A good example of forcing woody plants is cutting cherry branches (the so-called Christmas branches), which beautifully bloom in a vase by Christmas. Plant forcing is not complicated, but it requires a certain amount of patience and care. The principle of forcing is primarily based on the higher temperature at which the plants are grown. Some species are sensitive not only to temperature but also to the length of sunlight, so forcing such plants is more complex.

Blooming tulips create a spring atmosphere and chase away winter

The best way to create a spring atmosphere is with blooming flowerpots. Forcing bulbs is not complicated, but it requires preparation well in advance. A wide range of bulbs are suitable for forcing. Spring snowflakes, snowdrops, squills, tuberous crocuses, hyacinths, tulips, and daffodils are all suitable.

Bulbs intended for forcing are planted in pots as early as September. When planting, they are positioned so that their tips stick out. Light soil with added sand, peat, or perlite is essential. Only round bulbs, larger and visibly undamaged, are suitable for forcing. For tulips and daffodils at least 3 cm in size, for hyacinths 5 cm. Only these larger bulbs can be expected to have sufficient stored nutrients and bloom beautifully in spring. It is best to plant bulbs in groups of 3 to 5, as they look best during flowering this way. Only hyacinths are planted separately.

A very striking method is planting window boxes with several types of bulbs simultaneously.

It is good to place the containers in a cold frame or greenhouse (buried in the soil) and let the bulbs root there. After several months, they begin to be moved to spaces with higher temperatures. In December, you can start moving small bulbs such as snowdrops and spring snowflakes, in January hyacinths and squills, in February tulips, and at the beginning of March daffodils.

Watch out for growing temperature

Containers with plants should not be immediately exposed to room temperature; the plants must first be hardened off. First, the plants are placed in an unheated room or hallway where the temperature ranges between 10 to 12°C. After about two weeks, they can be moved to spaces with temperatures of 16 to 18°C.

Flowering occurs 3 to 6 weeks after removal from the greenhouse. The timing depends on the plant species and specific environmental conditions. Sprouting plants require adequate watering. After flowering, place the bulbs back into the soil, but in this case too, it's important to ensure gradual hardening (i.e., gradual temperature reduction). Bulbs can be used repeatedly for forcing, but not two years in a row.

Your Own Vegetables Easily and Quickly

Vegetables with shorter growing cycles are particularly suitable for forcing. The most commonly grown vegetable this way is head lettuce, but kohlrabi, tomatoes, cauliflower, peppers, salad cucumbers, and eggplant are also suitable. Radish is a very suitable and undemanding plant. For forcing vegetables, we preferentially use specially bred varieties, which are currently easily available in practically every garden center.

If you have a cold frame available, you can start gardening as early as the second half of March. Seed planting is best done in a planter box or other shallow container. Flower pots aren't very suitable at this stage–they're harder to handle and unnecessarily deep. The substrate must be light and airy. You can create it by mixing matured, sifted compost with peat, or perlite.

You can also purchase special mixes labeled "for sowing". Place the soil in containers, lightly compact and level it. Seeds are then planted either across the entire surface or in rows. Before planting, it's advisable to soak the seeds in water, which causes them to swell and promotes germination. However, let the seeds dry before planting in the substrate.

After placing in the substrate, water with settled water, ideally using a sprayer, which won't wash the seeds together. Repeat watering several times. Then lightly cover with soil and cover with a lid. Continue to ensure regular watering. If the seeds dry out, they most likely won't germinate. The ideal temperature for germination is 18 to 25°C. It's also important to regularly remove the top cover of the cold frame, which regulates temperature and air humidity. This prevents the development of mold.

When forcing, use a sprayer for watering. It's gentler.

The Next Phase is Pricking Out

Pricking out plants into pots is done when they have well-developed cotyledon leaves. You can use the same substrate as for sowing, or there are mixes labeled "for growing on seedlings" available.

Besides classic pots, it's advisable to use peat rooting pots, or yogurt cups with a drainage hole made in the bottom can also work well. Using special peat rooting pots is particularly advantageous because when transplanting into soil later, the plant's root system won't be disturbed and the container will decompose naturally in the soil. During transplanting, it's good to slightly trim the seedlings' roots, which promotes better root system development.

Light is Especially Important at the Beginning

For young seedlings, we ensure sufficient light supply, but don't expose them to direct sunlight, as this could cause burning. In case of insufficient light, excessive stretching occurs and plants become more fragile. During cultivation, it's important to maintain suitable temperatures.

Specifically, lettuce needs a temperature of at least 14 to 18°C during the day and 12 to 14°C at night for growth. However, some vegetable varieties are more sensitive to temperature (cucumbers, tomatoes). These varieties need a temperature of at least 20°C during the day and at least 12°C at night. It's not advisable to overdo temperatures in cold frames or greenhouses - temperatures above 30°C slow down photosynthesis intensity and thus halt plant growth. Excessive temperature fluctuations between day and night aren't good either, as this also inhibits plant growth.

Which Plants Do We Most Commonly Force?

• Root vegetables
• Peppers
• Lettuce
• Roses, gladioli, lilies