Tips And Ideas For Garden Lovers
Problem-The container plants look nutrient deficient
Nutrient deficiencies are the most frequent problems that containerized plants face. Roots can forage far and wide in the soil for the nutrients they need even a small plant's roots can easily extend 30cm (1 foot) or so deep in the soil and 3m (10 feet) or more wide but in a pot all the roots have to wrap around each other in a confined space. Roots often try to travel out of the drainage holes in search of new soil. But they will not get far and will soon become "air pruned" when they are not moist enough to survive.
Nutrient deficiencies show first as yellowing, purpling or mottled leaves. Next comes die back of growing tips and a general stunting. Insects and disease problems soon follow because weak plants are more vulnerable than healthy ones. The following solutions will help to keep your plants from suffering deficiencies.
Solution 1 Apply liquid fertilizers
Containerized plants need a great deal of water. Most require at least one watering a day, but in the hottest part of the season some require two waterings. It's important to water deeply (see 'Check for soluble salts,' opposite page 153), but when you do, you will also be washing nutrients out of the soil. More often than not, plants become nutrient deficient by mid season.
Liquid fertilizers are the remedy. If you want to work completely organically, choose a mixture of liquid seaweed and fish emulsion as your fertilizer. But rather than diluting it according to the directions on the bottle, use it at half-strength. This lighter concentration will allow you to apply it more frequently.
Synthetic liquid fertilizers are also available at any garden supply store. The plant label will generally recommend a dilution rate for plants in pots, but if it doesn't, begin by mixing it as directed on the package. Depending on how the plants respond, you can always adjust the mix.
Most plants do well with a weekly feed, but some especially vigorous growers may require feeding more often. Look at the leaves to determine nutrient needs. If the leaves are a strong green, the plants are getting enough nutrients. If they are a bit yellow or purple, they need feeding. If they are getting too much nitrogen and you need to cut back on fertilizing, the leaves will be too dark a color and grow too large. In some cases, they will be a little bit floppy and look as if they don't contain enough cellulose.
Solution 2 Check for soluble salts
Nutrient elements are made up of salts. In the garden, rain often washes excess nutrient salts out of the top layers of the soil, but in dry soils and containers salts can accumulate. If they do, plant roots have a very hard time picking up adequate moisture, even if the soil is wet, because the salts in the soil solution hold onto it. Without adequate levels of water, plants become drought-stressed and can also suffer nutrient deficiencies.
You can usually see salts building up. White crystals form on the surface of the soil and along the soil line on the inside of the pot. If the situation is not severe, you can leach the soil mix by top watering the plant until water freely pours from the drainage holes. Let a great deal of water wash through the soil. Subsequent to that, don't water unless the soil is really dry; when you do water, don't stop until water runs from the drainage holes, even if you are using drip irrigation.
If leaching the soil doesn't solve the problem, remove the plant from the pot and gently wash the roots with running water. Then pot it up again in new potting soil. Water thoroughly each time to 'avoid future problems.
Solution 3 Select the right soil mix
Soils with high levels of organic matter have several advantages. First, because nutrients are released slowly as microorganisms in the mix break them down and transform them into forms plants can use, fewer are available at any one time. This means that excess soluble salts are less likely to build up in the potting soil. Second, these mixes require less fertilization, therefore less maintenance time. Finally, the pH in these potting mixes stays more stable than it does in a mix composed only of peat moss, vermiculite, perlite and synthetic nutrients.
When you buy a potting soil, check the ingredients. Your guarantee that the mix has organic matter is the mention of compost or aged manure at the top of the list. Depending on where you live, you might have to check with several garden supply stores before you find a mix like this, but it will be well worth the trouble.
Solution 4 Add worms
Worms are the gardener's best friend, even in a potting mix. They tunnel up and down, creating pore spaces for air and water. They help to make nutrients available if the mix contains enough organic matter. And they help to maintain the slightly acid soils that plants require.
Worms will not fare well in a small pot, so there is no use adding them. But they do well in pots that are at least 20cm (8-inches) wide. You can add them anytime when you first fill the pot or later, when plants are actively growing. If you add them later, loosen the soil first so they can burrow away from the light immediately. Don't put too many worms in a pot. For pots between 20-25cm (8-14-inches), use two worms. Add 4 in pots 40-60cm (16-24-inches), and eight or more in half-barrel and large tubs.
You can usually find worms at the bottom of your outside compost pile or in your garden. Or check the web or look in the back of gardening magazines for suppliers.
Nutrient deficiencies are the most frequent problems that containerized plants face. Roots can forage far and wide in the soil for the nutrients they need even a small plant's roots can easily extend 30cm (1 foot) or so deep in the soil and 3m (10 feet) or more wide but in a pot all the roots have to wrap around each other in a confined space. Roots often try to travel out of the drainage holes in search of new soil. But they will not get far and will soon become "air pruned" when they are not moist enough to survive.
Nutrient deficiencies show first as yellowing, purpling or mottled leaves. Next comes die back of growing tips and a general stunting. Insects and disease problems soon follow because weak plants are more vulnerable than healthy ones. The following solutions will help to keep your plants from suffering deficiencies.
Solution 1 Apply liquid fertilizers
Containerized plants need a great deal of water. Most require at least one watering a day, but in the hottest part of the season some require two waterings. It's important to water deeply (see 'Check for soluble salts,' opposite page 153), but when you do, you will also be washing nutrients out of the soil. More often than not, plants become nutrient deficient by mid season.
Liquid fertilizers are the remedy. If you want to work completely organically, choose a mixture of liquid seaweed and fish emulsion as your fertilizer. But rather than diluting it according to the directions on the bottle, use it at half-strength. This lighter concentration will allow you to apply it more frequently.
Synthetic liquid fertilizers are also available at any garden supply store. The plant label will generally recommend a dilution rate for plants in pots, but if it doesn't, begin by mixing it as directed on the package. Depending on how the plants respond, you can always adjust the mix.
Most plants do well with a weekly feed, but some especially vigorous growers may require feeding more often. Look at the leaves to determine nutrient needs. If the leaves are a strong green, the plants are getting enough nutrients. If they are a bit yellow or purple, they need feeding. If they are getting too much nitrogen and you need to cut back on fertilizing, the leaves will be too dark a color and grow too large. In some cases, they will be a little bit floppy and look as if they don't contain enough cellulose.
Solution 2 Check for soluble salts
Nutrient elements are made up of salts. In the garden, rain often washes excess nutrient salts out of the top layers of the soil, but in dry soils and containers salts can accumulate. If they do, plant roots have a very hard time picking up adequate moisture, even if the soil is wet, because the salts in the soil solution hold onto it. Without adequate levels of water, plants become drought-stressed and can also suffer nutrient deficiencies.
You can usually see salts building up. White crystals form on the surface of the soil and along the soil line on the inside of the pot. If the situation is not severe, you can leach the soil mix by top watering the plant until water freely pours from the drainage holes. Let a great deal of water wash through the soil. Subsequent to that, don't water unless the soil is really dry; when you do water, don't stop until water runs from the drainage holes, even if you are using drip irrigation.
If leaching the soil doesn't solve the problem, remove the plant from the pot and gently wash the roots with running water. Then pot it up again in new potting soil. Water thoroughly each time to 'avoid future problems.
Solution 3 Select the right soil mix
Soils with high levels of organic matter have several advantages. First, because nutrients are released slowly as microorganisms in the mix break them down and transform them into forms plants can use, fewer are available at any one time. This means that excess soluble salts are less likely to build up in the potting soil. Second, these mixes require less fertilization, therefore less maintenance time. Finally, the pH in these potting mixes stays more stable than it does in a mix composed only of peat moss, vermiculite, perlite and synthetic nutrients.
When you buy a potting soil, check the ingredients. Your guarantee that the mix has organic matter is the mention of compost or aged manure at the top of the list. Depending on where you live, you might have to check with several garden supply stores before you find a mix like this, but it will be well worth the trouble.
Solution 4 Add worms
Worms are the gardener's best friend, even in a potting mix. They tunnel up and down, creating pore spaces for air and water. They help to make nutrients available if the mix contains enough organic matter. And they help to maintain the slightly acid soils that plants require.
Worms will not fare well in a small pot, so there is no use adding them. But they do well in pots that are at least 20cm (8-inches) wide. You can add them anytime when you first fill the pot or later, when plants are actively growing. If you add them later, loosen the soil first so they can burrow away from the light immediately. Don't put too many worms in a pot. For pots between 20-25cm (8-14-inches), use two worms. Add 4 in pots 40-60cm (16-24-inches), and eight or more in half-barrel and large tubs.
You can usually find worms at the bottom of your outside compost pile or in your garden. Or check the web or look in the back of gardening magazines for suppliers.
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