Q: Nothing is growing in my raised beds since I planted starts from in my garden at end the of April. I used these troughs last year with great success. What can I do to boost these sad-looking veggies. – Lane County
A: Growing vegetables in containers is more challenging than gardening in the ground because a container is a closed system. The only soil the plant has to grow in is the soil you provide, and the plant doesn’t have the option of sending roots deeper or spreading further to supplement its diet. If you used these troughs in the same location last year with great success, then you must be providing the right environment with enough light and you have watering under control. The slow start this year could be down to soil care or planting time.
If similar plants were growing in these containers last year, the soil may be depleted in the nutrients they need. Whether you are planting a new bed in the ground or in a container it’s good to add compost and apply a slow-release fertilizer about a month before planting time. This gives the soil organisms time to break down the fertilizer into a form that plants can use. After a season or two you can fertilize at planting time. When planting in containers, you should add fertilizer every two weeks because nutrients are flushed out with watering. Your plants are already in place, so use a complete fertilizer containing nitrogen, phosphorous and potassium (NPK) with numbers like 10-10-10 on the packaging. Worm casting tea or fish fertilizer will also keep your plants healthy. Yellowing leaves can be a sign that your plants are lacking in nitrogen.
If these vegetable starts were planted out late in April, they may still be suffering some transplant shock and the tomatoes like a soil temperature of 65 F if they are to continue growing without interruption. Often the soil doesn’t warm up enough in Oregon until mid- to late May or even June. There is more useful information in this publication on Vegetable Gardening in Oregon. – Stephen Oldfield, Oregon State University Master Gardener
courtesy: https://www.oregonlive.com/hg/2021/05/ask-an-expert-step-up-soil-care-when-planting-in-containers.html