Germination temperature - Adenium at home: from seeds to plants. Growing and care. Warm seedling mat made in China Seed warmer

How to do country house cozy and comfortable Andrey Petrovich Kashkarov

3.25. Heating the soil for seedlings and flowers using improvised means

February and March for gardeners and gardeners, residents of rural areas are a traditional time for growing seedlings in pots; the grown sprouts will later be transplanted into the greenhouse. Growing seeds in pots and greenhouses is not a whim, but a necessity, since both cold from above and frost from below (freezing of the soil) are dangerous for sprouts, and even slight hypothermia at subzero temperatures is enough to “kill” a seed.

With the help of a simple device, transformed from a household air freshener, I have been successfully growing seedlings for the fifth season. To do this, I use soil heating using a somewhat unusual, but low-cost and simple method.

How to do it? So, we take the household automatic air freshener shown in Fig. 3.15.

Rice. 3.15. An automatic air freshener can be purchased at Home Goods stores.

Without going into detail about the principle of its operation, which is far from the informal use of the “filling” of the device that I have tested, let us dwell on the features of organizing the heat source, which we will place directly in the soil.

We remove the replaceable flavor cartridge (Fig. 3.15) and carefully disassemble the white plastic case. To do this, you need to unscrew one screw from the side of the power plug.

Rice. 3.16. View of the heating element - black box with wires - heat source

Two conductors from the plug connector go to a black round box (Fig. 3.16), which will be useful to us for the heat source. All other “spare parts” from the once useful device will not be needed.

The next step is to unsolder (or cut off with side cutters) the conductors connected to the terminals of the black box, and carefully open its body using a sharp object: a knife or a flat-head screwdriver. Now the view shown in Fig. 3.17.

Rice. 3.17. View of the inside of the heater

Here we see two resistors (resistances) connected in series. Each of them has a resistance of 13.9 kOhms (a kilo ohm is a relatively large resistance), and the total resistance of the circuit is slightly more than 27 kOhms. When such a circuit is connected to a 220 V network, a current of 8 mA flows through the resistors (milliamps is a very small current), and they smoothly heat up to a temperature of +30...+40 °C.

This temperature will not rise higher, no matter how long you keep this device connected to the 220 V network.

Now we solder any network wire with a plug (plug) at the end to the resistance terminals (ready-made pieces of suitable wires with a plug are sold in an electrical goods store), insulate the ends (for example, with cambric or electrical tape) and close the lid of the heating element (Fig. 3.16).

Rice. 3.18. View of a reborn flower using recommended stimulation

We bury the closed heating element in a cuvette with seedlings or in flower pot(as in Fig. 3.18) and plug the plug into a power outlet. Soil heating is ready.

In Fig. Figure 3.18 shows the result of my experiment with the revival of a dried palm flower (the dry trunk of the former palm tree is clearly visible).

There was no noticeable growth for more than a year, during which time the once thick trunk itself turned almost into dust (from the inside). After stimulating the soil with the recommended device, in less than a month of stimulation, foliage growth exceeded all imaginable expectations.

Tomato seedlings, which I have been experimenting with for several years before planting in greenhouses, grow less quickly, however, thanks to heating the soil in the ditch with seedlings, now they do not have to be kept directly on the windowsill (as many do, providing the sprouts solar energy and light); I take several ditches out into the sun outside the window during the day already in mid-March (like this year), because even in the morning frosts the soil remains warm.

The current consumption from the 220 V network is so insignificant that it is not even noticeable on the electricity meter. For comparison, a typical 40 W incandescent lamp consumes 180 mA of current, which is approximately 22 times more than our miniature and economical heater.

The device is completely safe to use. The only note for flower growers: before watering a pot of flowers, unplug the plug from the power outlet. After the watering procedure is completed, you can turn it on again without waiting for the soil to dry out.

I also recommend using the device periodically: for example, stimulate the plant for 2 weeks, then rest for a week. Then repeat the prevention cyclically. This is necessary in order to eliminate the habituation effect of the plant and create the most favorable microclimate for it.

In 2012 alone, I obtained amazing results in floriculture: in addition to those described above, I managed to accelerate the growth of two large palm plants, dracaena and monstera.

This technique is simple and can easily be repeated by a gardener even without special knowledge of physics. Household fragrances similar to those shown in Fig. 3.15, have the same operating principle, and from time to time it is necessary to buy replaceable cartridge cylinders for them (sometimes the cost of such a replaceable “carrier of a delicious smell” exceeds the cost of the device itself along with one carrier). Sometimes cartridges cannot be found on sale, so the device becomes useless for its intended purpose. I not only gave it a second life, but I also successfully grow flowers and seedlings - to the delight of myself and my loved ones.

From the book Modern work on laying the foundation. Types of work, materials, technologies author

Ways to save money and materials when constructing foundations In low-rise individual housing construction, as a rule, strip foundations– prefabricated and monolithic. Strip foundations made from prefabricated concrete blocks are widely used in

From the book Fence, fence, gate on a summer cottage [We build with our own hands] author Nikitko Ivan

Fences made from scrap materials Often owners summer cottages save on materials for fencing, especially if finances are not very good or if the plot is small and the owner does not see much point in investing much money in it.

From the book Practical homemade crafts for the garden with your own hands author Team of authors

From the book How to Make a Country House Cozy and Comfortable author Kashkarov Andrey Petrovich

From the book Dacha Encyclopedia experienced advice author Kashkarov Andrey Petrovich

1.6. Magic balls for seedlings, and not only Aqua soil is a hygienic and aesthetic replacement for ordinary soil, recognized by experts. Almost any flower can grow in it without adding actual soil (soil). Aqua soil, also known as hydrogel, absorbs perfectly

From the book The Real Man's Handbook author Kashkarov Andrey Petrovich

From the book Modern Greenhouses and Greenhouses author Nazarova Valentina Ivanovna

Using alarm systems To ensure safety on the water, light-smoke buoys are installed. As an example, we can consider the light-fuming buoy BSD-02 (BSD-M, BSD-M2). Such a buoy is intended to indicate the location of a lifebuoy both at night and

From the book Cosmetics and Soap self made author Zgurskaya Maria Pavlovna

How to help a drowning person using available means? It is best to use a lifebuoy or Alexandrov's lifeline. Alexandrov's lifeline (a means for assisting drowning people) is a floating polypropylene line

From the book Greenhouses and Greenhouses. We build and grow author Kalyuzhny S.I.

How to quickly make a raft from scrap items? Take thick tree trunks, preferably of the same length, and tie them with hemp rope (as shown in Fig. 2.2) using two cross beams from smaller trunks. Tree trunks are first cleared of

From the author's book

How to catch an animal in the forest using improvised means? For hunting in the forest, as an option, a simple device made from two pointed crossed sticks is suitable (Fig. 2.10). It is thrown towards the animal with maximum throwing force. Rice. 2.10. Device

From the author's book

Using radio-electronic means to call for help With the help of an officially registered radio-electronic means, you will be able to perform the tricks described earlier (lighting lamps that are not screwed in anywhere or unauthorizedly turning on neighbors’ lights,

From the author's book

Soil disinfection technology The greenhouse administration organizes preparatory work. Inspects the tightness of greenhouses and carries out additional glazing, and, if necessary, insulating greenhouses from production premises using polyethylene

From the author's book

Features of sowing and preparing seedlings of vegetable plants for growing in residential premises Preparation and sowing Before sowing, the seeds are calibrated by size and weight. Full-bodied seeds are separated in a weak solution of table salt (20–25 g per liter of water); when stirring (in

From the author's book

Preparing seedlings Seedlings are used to grow cucumber, tomato, sweet and hot pepper, as well as lettuce, Chinese cabbage, purslane, and some perennials. aromatic plants. For room conditions It is more convenient to have picked seedlings. For this purpose, crops are usually thickened.

From the author's book

Chapter 4 Recipes for homemade cosmetics Below are recipes for drugs that will help preserve the youth and beauty of your skin, nails, and hair. Of course, there are much more effective formulations, but you can make and combine them yourself,

I want to tell you about several useful devices helping to grow excellent seedlings.

Seed sprouter

Preparation seed material - important stage, on which the success of the business as a whole depends. Some seeds need to be germinated before planting. This way, even before sowing, you can select the strongest plants, increase germination to almost 100%, and eventually get sprouts that appear together.

Modern sprouters have replaced saucers with wet gauze. They come in regular and aeroponic varieties. Simple models Sprouters are a small container that is filled with water to the required level. A mesh tray with seeds is inserted on top. The peculiarity of this germination method is that the seeds are only partially immersed in water.

The container is closed with a lid, which provides a favorable microclimate, creating a greenhouse effect. The mesh tray can have several compartments. This allows you to prepare several crops for planting at once. The cost of this simple, but very convenient device from 400 rub.

Aeroponic germinators are more complex in design, but the processes in them are faster. You can get results within 8-12 hours. The thing is that in addition to a container for water, a lid and a basket for seeds, aeroponic germinators are equipped with an air sprayer and electric compressor. With their help it is supported required level humidity in the container, which is why germination occurs. In this case, the seeds are above the surface of the water without touching it. The cost of an aeroponic germinator starts from 1000 rubles.

You can prepare in this way not only planting material, but also seeds intended to be eaten in sprouted form. In addition, in your free time from gardening, sprouters can be used to obtain fresh greens and grass for animals.

Propagator

Essentially, a propagator is an indoor greenhouse that eliminates the need to constantly wrap seedlings in film and cover them with glass. The simplest propagator is a crease-resistant container with a transparent lid, which has adjustable ventilation holes. The lid is usually high so that the plants can remain in the container for as long as possible. favorable conditions. Thus, seedlings from the propagator can be planted directly onto the beds. More complex models have heating, lighting and humidification. To maintain a microclimate favorable for plants, they can be equipped with automation. This greatly simplifies the care of seedlings, allowing you to leave them unattended for several days.

Using a propagator you can quickly get the same healthy seedlings. You can also germinate seeds in it. The cost of such equipment starts from 1000 rubles, and the more functions it has, the higher the price.

An analogue of propagators are grow tents. They differ large sizes and, as a rule, more powerful equipment. For such equipment you will have to pay more than 10,000 rubles.

Mat for heating seedlings

For better germination and obtaining early seedlings, you can use special infrared heating mats. They are placed under containers with crops and simply plugged into the network. They don't dry out the air. Their peculiarity is that infrared heat warms the soil to the desired temperature, while losing a minimum of energy to warm the air. After all, for growth it is more important that the earth is warm, not the air. This feature allows you to obtain the required result with minimal financial costs for electricity.

The effectiveness of mats is to increase seed germination by almost half. Depending on the size and manufacturer, such a rug can cost from 1000 rubles.

Peat tablets

What do you need to plant seeds for seedlings?

Cups, soil, scoop?

Modern solution - peat tablets. These are small cylinders that increase in height by almost 7 times as they are moistened. Added to the substrate necessary fertilizers, which contribute to the proper growth and development of the plant. They will be enough for the time until the plant is transplanted into the ground. The cost of such a tablet is about 20 rubles. There are more cheap analogues, but they most likely will not have a reinforcing shell, and as the plant grows, the peat cylinders will begin to fall apart, exposing the root system.

Another modern way growing seedlings - using organic plugs. They are made from recycled tree bark and composted products. The seeds are placed in special holes. One organic cork will cost 50 rubles.

These types of tablets and plugs are especially convenient because they can be used as a substrate for hydroponic growing of seedlings.

Hydroponics

A method of growing seedlings called hydroponics is becoming increasingly popular.

A plant grown using this technology constantly receives the necessary complex of nutrients required for proper growth and development. In addition, adherents of hydroponics talk about further increased plant viability and, as a result, greater yield.

The principle of the hydroponic method is that the plant takes root not in the soil, but in a neutral substrate, partially immersed in a nutrient solution. Today you can find a lot hydroponic installations various types and sizes. Essentially, they all consist of a container for the nutrient solution and a submersible basket for the substrate.

Substrate quality plays a role important role in the effectiveness of the technology as a whole. It must hold liquid and air in sufficient volumes. The most popular types include coconut fiber, expanded clay, perlite, fine gravel, moss, mineral wool, peat, blast furnace slag, hydrogel, or a combination of several substrates.

The variety of hydroponic devices includes both the simplest (a container with a basket) and more functional settings. They can circulate a nutrient solution, which provides better nutrition to the root system, and be fully automated. The cost starts from 1000 rubles. But we must not forget about the need to use properly selected nutritional compositions. They cost from about 500 rubles. for 250 mp.

It is also possible to grow seedlings using aeroponics. In this case, the plant receives nutrients with the help of small drops of the nutrient composition, raised by the aerator to the root system. It doesn't even require a substrate.

The simplest aeroponic installation on a windowsill can be purchased for 1000 rubles. It will also require nutritional compounds.

Phytolamp

Many people are faced with the fact that seedlings grown on a windowsill stretch out. Instead of a strong plant, something fragile and obviously not entirely healthy has to be planted in the beds. As a result, some break, and some die after landing. It's all about the lack of light. Short daylight hours and cloudy weather cannot but affect the plants, especially during the period when they have not yet become strong and are only gaining strength. You can solve the problem with the help of phytolamps.

In an apartment, it is best to force seeds in mini greenhouse. Some will ask: why? After all, the apartment is already warm and light, let it grow the old fashioned way in boxes! They've been growing this way for decades! That’s how it is, but how much energy can be saved when leaving and to what extent? improve the quality of seedlings, if you use a mini-greenhouse for this!

The apartment has far from ideal conditions - the air is dried out by central heating, winter-spring sunlight insufficient for plants, cold air blows from the window, etc. And tender seedlings need greenhouse conditions.

Mini-greenhouse on the windowsill

The window is the place where pots with indoor flowers and winter mini-beds with onions, parsley and dill are traditionally placed. Why not organize a small aesthetic greenhouse here that would decorate the interior?

For greenhouses located on window sills, there are certain requirements:

the main thing is that it should be aesthetic and not completely block light from the window, so as not to cause inconvenience to household members;
create for plants optimal mode;
provide easy access to plants for care;
have a good supply strength for reusable use.

Installing a mini-greenhouse on a windowsill will allow you to save energy on additional lighting. During the day, the sun will shine on the plantings, and you can extend the daylight hours with phytolamps.

Another advantage is the battery central heating. Bottom heating of the greenhouse will be provided without additional devices and costs.

Types

There are a great many types of mini-greenhouses on the windowsill, from simple cookie containers to complex automatic designs produced by industry.

Greenhouse from a container

It's easy to make mini-greenhouses for sowing seeds from plastic food containers. Such a container should be deep enough and have a convex lid so that the seedlings have room to sprout. And they look neat and are easy to care for. They need pallet where excess water will drain after watering. At the bottom of the container, just make a couple of drainage holes - and the greenhouse is ready.

If you make a neat rack around the perimeter of the window, you can fit many of these greenhouses on its shelves. The seedlings will grow in them until the time comes to plant them in separate pots.

"Houses"

If the window sill is wide, you can put it on it miniature copy garden greenhouse – small house with opening front panel. In it, already picked seedlings can be grown in cassettes.

In addition to seedlings, in such a greenhouse you can all year round grow greens, salads and even radishes.

Breadbox

It will look great on the window greenhouse-bread bin. Transparent from all sides, it will provide good lighting plants. For maintenance and ventilation, it can be opened with one movement of the hand. If the window sill is fully adapted for a mini-garden, it can be made to its full length.

In this mini-greenhouse you can even grow in cassettes early radishes.

Old aquarium

If you need a mini-greenhouse, but don’t want to waste money and time, use the old one aquarium(if there is one in the house, of course). The only thing you have to do is a transparent cover.

Such a greenhouse is good for everyone, one inconvenience is that you will have to get to the plants through the top.

What are we growing?

The choice is great and it depends only on your enthusiasm for selecting varieties of vegetables that can grow in a mini-greenhouse on the windowsill.

greens –, etc.;
tomatoes of the "" variety - yield up to 2 kg per bush (the weight of 1 fruit is no more than 30 g), suitable for fresh consumption, canning and freezing;
spicy . A bush with fruits can become a decoration for your interior, it looks so beautiful;
leafy ones - watercress, arugula, spinach;
early;
seedlings

Some craftsmen even manage to grow them on window sills.

Do it yourself

You can buy a mini-greenhouse for your windowsill; fortunately, there is no shortage of offers from manufacturers. The advantage of this solution is the absence of manufacturing hassle, the disadvantage is that it is not always possible to select right size, and you will still have to install additional lighting.

The advantage of a homemade greenhouse is that you can make a mini-greenhouse exactly according to your needs and it will cost less. The downside is that you have to tinker.

Rack

The most aesthetic and convenient option there will be a shelving made around the perimeter of the window. To make it look organic, it is better to make it entirely from durable polymer white or transparent material. The best will be the good old one plexiglass. It's durable unbreakable material. Its thickness should be from 10 to 12 mm.

Where to begin?

Of course, from the drawing and measurements. Plexiglas is easy to process and does not require complex instruments. All you need is a cutter for plexiglass, which is easily obtained from a hacksaw blade, a file to straighten the edges of the cuts, a screwdriver for attaching shelves to the walls of the rack, a marker for marking, and a drill.

cut out of plexiglass according to dimensions side walls and shelves;
the edges are processed using a file;
on the side walls, the points where the shelves will be attached are marked with a marker;
holes for the corners are drilled at the marked points;
fastenings are screwed on and shelves are inserted;
To give the structure additional rigidity, ties can be made from narrow strips of plexiglass behind the upper and lower shelves.

For sustainability On the lower part of the walls you can make “shoes” from small wooden blocks, making deep grooves on them and inserting the side walls there.

The rack is ready. It is convenient to place containers with seedlings and mini-beds with herbs on the shelves. You can decorate with small pots of indoor flowers.

Shelves can also be made hanging, as shown in the photo. But in this case it is impossible to make a greenhouse out of it using a cover.

For additional lighting, you can attach under each shelf phytolamp so that it illuminates the shelf with plants located underneath it.

If heating of the soil is necessary, you can use electric heat mats by placing them under the containers. If you need to create microclimate– it is always convenient to cover such a rack with a zippered film cover.

Conclusion. A beautiful and functional mini-greenhouse made by yourself will not only bring satisfaction from quality work done, but will also help to grow good harvest on window mini-beds. Good luck and new ideas!

Do-it-yourself budget mini-greenhouse? Easily!

If you find an error, please highlight a piece of text and click Ctrl+Enter.

Germination temperature

No matter how different the advice is on the composition of the soil mixture, the depth of planting, or the advisability of pre-sowing soaking, there is one prerequisite for the germination of adenium seeds - temperature. It should be 30-35 0 C. At lower temperatures, the probability of seed rotting is very high.

There are heated greenhouses, but I haven’t come across them in Russia, although I looked for them. If you live in a southern climate, natural temperatures will be sufficient in the summer. The rest were less fortunate in this regard, but winter will equalize the sowing conditions for everyone. So the adenium growers came up with this idea different ways temperature increases for all seasons.

So how to achieve the desired temperature?

1. Central heating batteries.
Salvation was found in what houseplants Central heating radiators usually suffer greatly. For the first time they can serve us well.

It’s easy to organize: take the greenhouse and place it on the radiator.
Just keep in mind that overheating, as well as cold, can negatively affect germination. To avoid “cooking” the seeds, the temperature must be adjusted in advance. For this you will need a thermometer, towels/books. It is not enough to simply place a container with seeds on the battery; you need to monitor the temperature with a thermometer. Otherwise, everything may end in failure, because... The correct temperature cannot be determined by eye. For humans, +35 degrees is warm and +40 is warm, and for seeds - this is already a big difference.

Place the thermometer in the place where the greenhouse will be located and measure the temperature. It will almost certainly be higher than the required limit. To regulate the temperature, we use towels/books, placing them on the radiator. When the layer lowers the temperature to the desired level, place the greenhouse on it. All.

2. Towel dryer in the bathroom.
The advantage is that it is available all year round. The disadvantage is that there is absolutely no light, so you should not delay in transferring the seedlings to a lighted place.
Otherwise, everything is the same as with central heating batteries.

3. Incandescent lamp (LN).
For a long time it has been used in households not only as a source of light, but also as a source of heat. For our purposes, a 40W lamp is suitable, more is possible, but then it is more difficult to “extinguish” the excess heat, and the electricity consumption is higher.
The disadvantage of using LN is round-the-clock lighting.
Using LN, you can organize bottom or top heating, depending on which one is more convenient for you.

Let's look at both:

Bottom heating : lamp below, greenhouse above.

Simple design: place 2 supports on the table (from books, pots, etc.), and place a greenhouse on them. Between the supports, under the greenhouse, there is a lamp. The temperature is measured with a thermometer and adjusted by the height of the supports.

Please note that the lamp emits heat not only upward, but also downward. Therefore, you need to protect the table surface from it, for example, using a ceramic plate/pallet.

Complex design: involves the use of a ceramic pot. It’s difficult to explain in words, it’s easier to depict it in a picture.

To regulate the temperature, you can also use books as a layer between the pot and the greenhouse. Advantage of the design: the surface on which the structure stands does not overheat.

Top heating: lamp on top, greenhouse on bottom.

The disadvantage of upper heating is that the lower one is more effective - the heat is directed primarily to the seeds, and not to the top of the seedlings. Plus - the lamp still provides light, although it is definitely not enough for full growth, but it is better than nothing. But the main thing is that, after replacing the LN with CFL (compact fluorescent lamp), we can easily convert a greenhouse for germinating seeds into a greenhouse for growing seedlings (small quantities).

There's no point in listing everything possible options structures, there are too many of them (someone even manages to hang greenhouses from the lamps).

I will only mention the simplest ones:

Desk lamp. There’s not even anything to talk about here - a greenhouse on the table, under a lamp, and that’s it. And if you do it on a bright windowsill...

Measure the temperature; if it is too high, place the lamp on the same books. The lamp comes with an alligator clip, so it can be hung.

Carrier and bucket. A greenhouse is placed at the bottom of the bucket. A strip (ruler, stick, etc.) is placed on top of the walls, to which a socket with a lamp is attached.

Instead of a bucket, you can use an aquarium or some other object as a support (box, box), the meaning will not change.

If you wish, you can use the upper and lower heating structures and build a combined greenhouse that is simultaneously suitable for germinating seeds and growing seedlings. The bottom line: LN at the bottom, CFL at the top, in the middle of the greenhouse.

4. Heated mat.

The season for growing seedlings is beginning (and for some has already begun in January), so this material about arranging heated seedling boxes will be very useful.
For the germination of certain types of plants that prefer high temperature, it is necessary to create additional heating. For example, vegetative development in cacti, coffee, adenium, etc. fully takes place only at a soil temperature of at least 30 C. And if, say, you need to root cuttings of bougainvillea, acalypha, cordyline, codiaeum, minimum temperature should be around 25 C. Even growing eustoma requires maintaining a temperature of 21 degrees Celsius, and on an unheated loggia in the spring such a climate rarely occurs.
As a rule, the “weather” in the apartment is not exactly what is needed for heat-loving seedlings, so you will have to provide suitable conditions yourself.
The simplest thing is to place the container with the seeds on some constant source of heat: a radiator, a heating pad, an electric heater, etc. But the battery will only help in winter, and electric heater It is not recommended to keep it on all the time; besides, it burns oxygen.
It is best to make a simple heating system with your own hands. You will need a large flower pot with a drainage hole or other similar container, an electrical cord and plug, a 15 W incandescent lamp and an electric socket.
We pass the cord through the drainage hole, leaving the plug outside, connect the cartridge to the other end of the wire and secure it to the bottom of the pot. We place dishes with seedlings or seeds on the pot.
Thus, the surface on which the pot is installed does not overheat and the heat will be used purposefully.
Instead of a pot, you can put two benches of the same height, put a sheet of thin plastic or other material between them and place a cuvette with plants on the sheet, and place a lamp with a reflector under it so that the heat goes up. In general, there are many options for how to make bottom heating.
It is important to adjust the temperature correctly so that it is optimal for the plants. To measure, use a room thermometer, placing it in the place where the bowl with seedlings will stand.
Most likely, the temperature will be higher than required, so to adjust, take a thin book and place it on top of the pot, making a spacer between the container with the cuttings and the lamp. Required thickness You can easily select gaskets experimentally.
A more advanced method is to use a “warm floor” system for heating. The choice of these systems on the market is huge, but the cost varies from 1000 to 5000 rubles per square meter such pleasure. The supplied regulators will allow you to set the desired temperature and not waste electricity.
Another solution is special heated mats for animals and reptiles. Honestly, I have not seen such mats in our pet stores, but if you open Chinese aliexpress.com or the same ebay.com, by searching for “heated pad” you will find a huge number of mats for every taste and color. The cost of such a rug ranges from 200 to 1500 rubles per piece. In my opinion, for plants this is the most best option in terms of price-quality ratio. But the situation with Chinese orders is worsened by our Russian Post, which will deliver the parcel only in a month, or even two. Here is an example of such a rug for 7 bucks:

If you also use a timer, which will automatically turn on the heating during the day, and at night the temperature will drop to room temperature (if this is necessary for a specific type of plant), then this option will simply ideally maintain temperature regime, recommended for growing most plants.
As you can see, making bottom heating is not at all difficult, and now you can do any operations with heat-loving plants, for example, growing cacti from seeds.

Estimate