Watering Hostas (Calculator)


Hostas like to grow in the shade, but they evaporate a lot of moisture due to the large leaves. As a result, there is a water shortage, and the roots begin to absorb it from the soil.

In the absence of moisture, the leaves may wither. Therefore, you should keep the soil constantly moist around the hostas. The picture below shows how to properly water the hostas depending on different conditions.

Hosta Watering Calculator

garden pots

Number of waterings in a drought: time(s) per week.

Amount of water: gallon(s).

© worldofgardenplants.com

Of course, this is indicative because watering depends on many different factors that are difficult to place in one scheme. Next, I will describe everything in as much detail as possible.

How much and how often to water hostas?

In the absence of rain (more than a week), dwarf and medium varieties of hostas should be watered once a week, the amount of water for each plant should be 0.3-0.5 gallons of water (1-1.8 liters) depending on the size of the bush. Large varieties should be watered once a week with 1 gallon of water (3.7 liters).

If the drought and the sunshine very bright, you need to water twice a week. The following table clarifies the watering issue a bit more.

Conditions Frequency and Quantity
Big and Giant 50-80 inches (1.2-2 m) wide 1 per week if no rain in half shade with 1 gallon (3.7 liters) of water.
Dwarf and Medium 15-40 inches (0.3-1 m) wide 1 per week with 0.3-0.5  gallon (1-2 liters) water.
Summer If very hot and dry, water large hostas 2-3 per week with 1 gallon (3.7 liters) of water. Small and Medium 1-2 per week with 1 gallon (3.7 liters) of water.
Spring Water large hostas once a week with 1 gallon of water. Small and medium hostas need 0.5 gallons of water.
Fast Draining Soils In sandy soils, large hostas water at least 2-3 times a week with 1-2 gallons of water if the weather is dry. Medium and small hostas 1-2 times per week 1 gallon of water.
Clay Soils In clay soils, watering is needed when the top layer of soil begins to dry out.
In Pots In the summer drought, large potted hostas need daily watering—small and medium every two to three days. One gallon of water usually enough.
Sun In sunny, dry weather, large hostas that can grow in a sunny place need watering once every two days with 2-3 gallons (7.5-11 liters) of water. In extreme heat, water them daily.
Shade On average, shaded hostas need watering once per week.

Different varieties need different amounts of water

Depending on what kind of hostas you have, watering will be different. Some varieties need more water and others less. The size of the bush is also essential. If the variety is large, but the plant is still young, it needs less water than a mature bush. Let’s dig a little deeper into this.

For convenience, I combined all the hostas into two groups – large and small. Small hostas can go a little longer without watering because their leaf area is smaller and evaporate water more slowly.

Watering dwarf and medium hostas

The group of small hostas includes dwarf and medium varieties. Their size ranges from 15-40 inches (0.3-1 m). Below is a list of the most popular varieties in this group.

Dwarf and medium varieties:

  • Blue Mouse Ears
  • Praying Hands
  • White Feather
  • Fire and Ice
  • Fire Island
  • Autumn Frost
  • Halcyon
  • June
  • First Frost
  • Stained Glass
  • Golden Tiara
  • Gold Standard
  • Minuteman
  • Liberty
  • Great Expectation

In dry weather, these hostas need watering once a week. The amount of water should be 0.3-0.5 gallons (1-2 liters). This is if they grow in shade or partial shade.

In hot and dry summers, watering should be increased to two or even three times a week. This is especially true for arid climates hardiness zone 8. The amount of water can also be increased to one gallon per plant.

Most compact hostas do not tolerate direct sunlight, except for Hosta ‘June Fever’. If you have a compact hosta for the sun, water it two or three times a week with one gallon of water.

If there was precipitation during the week, then watering is probably not needed, but we will discuss this issue below.

Watering large and giant varieties

Large hostas and especially vigorous varieties require a lot of water. The largest amount of water is necessary for large adult hostas that grow in big trees’ shade. This is because there is competition for water between plants, and the hosta can not win against trees.

Also, large varieties that grow in the sun need additional watering. Below you can see a list of the most common varieties of significant size.

Large and Giant varieties:

  • Empress Wu
  • Parasol
  • American Halo
  • Blue angel
  • Patriot
  • Frances Williams
  • Francee
  • Sum and Substance
  • Elephant Ears
  • Elegans
  • August Moon
  • Halcyon
  • Royal Standard
  • Wide Brim

In temperate climates, large hostas should be watered once a week with one gallon of water. The further south, the watering should increase.

In dry weather and with many sunny days, water every two days and increase the amount of water to two gallons or more if necessary.

When growing large hostas in the sun, you will have to water them almost every day. Here you need to pay attention to how quickly the soil dries around them. As soon as 0.5 inches of soil dries, water them immediately.

If you have many large hostas, then it makes sense to install automatic watering. In my opinion, the best solution would be drip irrigation. This way, you will be able to give the exact amount of water for each plant.

Hostas should be watered when it’s not raining

In not very hot weather, but the absence of rain, the top layer of earth usually dries out within 5-7 days. Therefore, you need to water the hostas at this interval. Large varieties are watered weekly with one gallon of water and compact with half a gallon.

In extreme heat, watering should be doubled. Twice a week for large varieties, two gallons of water, and one gallon for small hostas. This is if they are placed in the shade.

Hostas require at least 1 inch of rainfall per week. So if the weather is cloudy and rains a little, then for dwarf and medium-sized hostas, watering is usually not needed. Although there may be exceptions if you have sandy soils and the water drains too fast, then a little watering is still required.

For large ones, a little rain is good. However, rainwater may not be enough. It often happens that the sun shines brightly for 3-4 days, and the soil dried to a depth of 2 inches. Then a light rain passed, and the ground got wet by half an inch. From the above, it seems that the soil is completely moist, but this is not true. As a result, the hostas do not receive enough water.

In this case, I recommend checking with your fingers or a stick to see how deep the rainwater has penetrated. If there is dry soil under the wet layer, then you need to water your hostas.

This is especially true for large varieties because the roots of small hostas are higher and can draw water from the top layer of soil, not the case with large ones. With a small amount of precipitation, large hostas water with one gallon of water once a week.

With heavy rainfall, you should not water the hostas because excess moisture can cause root rot. This most often happens in areas where clay (slow draining) soils are common.

How often should I water hostas in the sun?

Most of the previous recommendations were about growing plants in full sun or partial shade unless otherwise indicated. In this chapter, we will talk about how to water the hostas growing in the sun.

There are not so many varieties that can tolerate direct sunlight. In particular, they include:

  • August Moon
  • Sun Power
  • Sum and Substance
  • Piedmont Gold
  • June Fever
  • and others

These are usually large varieties, but sometimes there are medium-sized.

If the weather is cloudy or little sun and there was no precipitation for seven days, the plants should be watered once every two or three days, depending on how quickly the soil dries. For large hostas, the amount of water should be 2-3 gallons; for medium, 1-1.5 gallons should suffice.

In case of severe heat and drought, daily watering may be required. The amount of water should be at least 3 gallons for large bushes and 2 gallons for small ones.

In the southern United States (zone 8), further increases in irrigation may be necessary. You need to check soil moisture. Water so often that the soil around the plants always remains slightly moist.

I do not recommend planting dwarf varieties in full sun because they can not withstand extreme heat and burn. The same applies to hostas planted in pots; you can not cope with watering in the sun.

Watering requirements depend directly on the type of soil

Depending on its type, the frequency and amount of watering can vary greatly. Let’s consider the topic of watering in terms of soil.

Fast draining soil

This type of soil includes sandy soil or loam. In some areas, the soil is common with a large number of small stones. Such grounds pass water very fast and dry up quickly.

If you have a similar soil composition in the yard, you have to water your hostas often enough. Large plants will need to be watered 2-3 times a week with 2 gallons of water or more often. The compact cultivars need 1 gallon of water.

Here is one option to simplify the situation. You can improve the quality of your soil, after which it will retain water better. To do this, when planting, add 15-25% compost and mix well. Use only suitable and quality compost. After such improvement, watering should be made as in the usual soil.

Slowly draining soil

For many plants, such a substrate will not be very suitable, but the hosta is an exception. These plants will grow well in moist soil. There are examples of the successful cultivation of these plants in pure clay. In this case, you will have to water the hostas once every ten days during the absence of rain.

If your soil retains moisture well and is at least a little loose, then everything is ok. Water the hostas in the usual way, as I wrote at the beginning of the article.

However, if you have clay in the yard or other types of heavy soils, I recommend loosening it a bit. When planting or transplanting hostas, add 15-20% compost or peat and mix it. This will make it easier for the plants to spread.

It may also be the case that in some areas, groundwater rises very high. Hostas love moisture, but they won’t survive in the swamp.

So if you have a similar situation, then be sure to make drainage under each plant. To do this, when planting, fill the bottom of the hole with a layer of stone or claydite 2 inches thick.

Watering hostas in pots

Potting soil, in dry and hot weather, dries out very quickly. It can happen in one day. Therefore, if you grow hostas in pots, you have to pay more attention to them.

The first thing to do is plant hostas in large containers so that the roots are not entangled. I recommend that the pot was 1.5-2 times larger than the size of the bush. The soil should retain moisture well, and compost is ideal for this.

Under such conditions, you will have to water the hostas twice a week with 0.5-1 gallon of water, depending on the plant’s size, in extreme heat, water every two days or even every day. To determine precisely whether a hosta needs water, check the soil if it is dry, water it generously. Excess water will flow through the drainage holes.

Also, I do not recommend planting hostas in pots with large drainage holes or too many holes. Otherwise, the substrate will dry too quickly. Two or three holes will be enough.

Large and giant hostas should not be planted in containers, as watering them will be too troublesome.

Also, do not place hosta pots in full sun, even if there are varieties that tolerate the sun. Because in the sun, you may not have time to water the plants, and they will fade or burn.

When to water hostas (best time)?

The best time to water the hostas is early morning. The advantage of this time of day is that the water will have time to penetrate deep and saturate the soil.

If you water when the sun is already shining hard enough, then some amount of the water evaporates, and you have to water again.

Another advantage is that by the end of the day, the surface will not be too wet, and it will be harder for snails to move on it. Therefore, your hostas will be a little more protected from these pests. This distinguishes morning watering from evening watering, and if you water in the evening, the snails will be more comfortable to get to your plants.

Another disadvantage of evening watering is that in wet soil and lack of sun, fungal spores and rot are easier to grow. If you water in the evening, it increases the risk of diseases.

Overwatering hostas

Overwetting hostas is quite difficult, although it can happen, so let’s consider the most common causes and how to avoid them.

First of all, it’s heavy rains. Sometimes it happens that the rain can fall for almost a month without a break; if you have clay in the yard, then the roots may rot. What to do to improve the soil I have already written above.

Incorrectly configured automatic watering. Some auto-irrigation systems turn on the water too often, almost daily or the day after the rain. It is not very good, even for hostas that love moisture. And if there is no drainage under the plants, it may not end well.

High level of groundwater. Groundwater itself will not harm the hosta, and in fact, experienced gardeners say that if the groundwater in the yard reaches the roots of hostas, it has a good effect on their growth. Problems still can arise with prolonged rain or snowy winters, though. So if this is your case, be sure to do drainage.

Another common mistake is planting hostas near the rain pipe. When rainwater is constantly flowing near the hosta bushes, it will end with the rot of the crown or rhizome. So, avoid this mistake.

Not enough water (underwatering)

Many people wonder what will happen if the hostas do not get enough water.

The first result of a small amount of water will be a lag in growth. The hostas will not reach the size that is inherent in a particular variety. In some cases, this is good, for example, if you do not have enough space and want to keep the hostas compact.

More serious consequences will be withering leaves. If you water hostas in time, the leaves will become normal, and everything will be ok. In the worst case, the leaves wither and dry out. The plant will not resume until next year.

If the hostas grow in the sun and water them untimely or give them not enough water, they can get sunburn or leaves scorch. In this case, the plant will look awful all season. So water the hostas on time and with enough water.

How often should I water hostas at different times of the year?

I wrote above about watering in the spring when the leaf has opened, all summer, and part of the fall until the leaves have turned yellow. Watering will be different at other times of the year, so let’s take a quick look at this topic.

In autumn, when the leaves turn yellow, the plant does not need much watering as before. However, this does not mean that the plant does not need water at all.

Usually, in autumn, there is plenty of moisture from the rain. If the rainfall is not enough and the ground is dry, you need to water the plants.

The fact is that if the plant has no leaves, it still needs a small amount of water. If there is no water, the plant begins to use internal reserves, and the rhizome starts to decrease in size.

You need to saturate the hostas with water for the winter because, in winter, the plants live mainly on internal water reserves. Water the hostas during the fall so that the rhizome absorbs as much water as possible. No need to swamp the ground around; keep it slightly moist.

I also recommend pouring a thin layer of mulch (0.5 inches) on top of the crown. This will not allow the sun to dry the crown if there is no snow. In early spring, the mulch from the top of the crown should be removed.

In the spring before the growing season, watering hostas is usually not necessary. After the winter, there is a lot of moisture in the ground, and the hostas will have enough of it. Only in rare cases of spring drought plants need to be watered.

Watering hostas after planting (newly planted)

After planting or transplanting, hostas need a special regime of watering. Because when you plant them in a new place, the growing conditions change greatly, and the plants need time to survive the transplant shock and adapt to new conditions.

The first thing you need to do is a water well before planting. In a few days, water them generously two or three times if there was no rain. In this way, the plants will get enough water for better rooting in the new location.

When the plants are planted, water them for the first time with not too much water. After 1-2 hours, water them again with a generous portion of water.

Next, you need to keep the ground moist but not swampy until the hostas take root. If necessary, water daily or every other day, do not let the soil dry out.

Mulch hostas to reduce watering frequency

The use of mulch is a great choice when growing hostas. If you mulch your plants, almost half of the watering frequency can be reduced, although it depends on what you used as mulch.

One of the best materials for mulching is pine needles. This material contributes to a brighter appearance of plants, and it has several other advantages. In particular, the air has better access to the ground around the plant. However, the needles retain moisture worse than, for example, pine bark.

The next good mulching material is pine bark. I recommend using a bark that is chopped into pieces of at least 1 inch. This mulch will perfectly protect the soil from moisture loss. Besides, against the background of the bark, the hostas look unique.

Compost also works well as mulch. It retains the soil better than other materials. It also makes the land more nutritious. As a result, you get a double benefit.

Another advantage of mulching is that in summer, the soil does not heat up too much, and in winter, the summer heat is delayed longer. As a result, the plants overwinter more comfortably.

The mulch layer should be 1 inch thick in the case of pine bark or compost and 4 inches if you are mulching with pine needles. There should be a 0.5-1 inch gap between the mulch and the stems so that the stems are not always wet.

Igor Viznyy

Hi friends, I have been growing plants for many years and love doing it. You can find more information on the page About Author.

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