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Gardening Questions Answered

A female gardener uses a blue spatula to dig the soil in a raised bed with growing pepper seedlings.

Because we are committed to inspiring and educating the gardener in you, we answer a lot of gardening questions to help you be successful. We asked you via social media to give us your gardening questions and we would answer! Below are the most popular.

All About Lettuce

Q. Can you grow lettuce in long containers? 2. What is good depth? 3. What makes lettuce bitter? 4. If it becomes bitter should I start over or just cut off? I had some lettuce I planted last fall that sat out all winter and has been growing but it is bitter. 5. Can you grow lettuce inside under lights when it is too hot outside and what is too hot? 6. And lastly, at what point should you start new plants if you’ve been harvesting leaves off your plants.

A. Absolutely! It sounds like you might be describing window-box style containers that are both long and semi-shallow. Lettuce has shallow roots and is a great candidate for these style containers as long as they have drainage.

  1. A minimum depth for lettuce would be 4″, but 6″ is even better.
  2. Lettuce can become bitter when it undergoes stress from conditions like heat, drought, or being rootbound; also, if it is past its prime, it can produce a flower stalk which causes it to produce a milky, latex substance that gives it a bitter flavor.
  3. If lettuce becomes bitter you should start over. It is a good idea to sow lettuce every 3 weeks for a continuous supply.
  4. You can grow lettuce indoors when it is too hot outside. Some varieties are more heat tolerant than others, but temperatures in the 90s can be too warm for many lettuces.
  5. As long as the plant is producing quality leaves, you can keep harvesting. Once lettuce begins to bolt or turn bitter, it is a good idea to start fresh or you can stick to the succession sowing schedule of every 3 weeks for a continuous supply.

There is more information about growing lettuce in our Lettuce: Sow and Grow Guide, along with some information on bolting, and an article on heat tolerant lettuces and greens.

Low-Light Vegetables

Q. What vegetables can be grown in a low light balcony? I’m just wondering how much direct sun should leafy greens get? I’m thinking of making a separate bed for my leafy greens in a more shaded area.

A. Great questions! An ideal situation for all vegetables is 6 hours or more of direct sunlight a day, which is what is meant by “full sun”. The good news is that there are a lot of healthful edibles you can grow in in lower light or even containers.

Greens like lettuce, arugula, kale etc., and also herbs. In lower light, crops may take longer to mature, but your patience will be rewarded. Read about other options that can work in low light in our article, Edibles for Partial Shade.

Seeds or Starter Plants?

Q. Which plants are better to start from seeds and which from starts?

A. Ah yes, a lot of gardeners have this same question. Here’s the short of it–root crops and other crops that do not do well with root disturbance (e.g. carrots, beets, beans, squash) along with quick-to-mature crops, are best “direct sown” in their final growing location.

However, if you live in a climate with a short growing season, you may have to make an exception and start some transplant-sensitive crops indoors and transplant them out when young so they will mature in time before your fall frost.

Crops that take longer to mature and are not as sensitive to root disturbance (e.g. tomatoes, peppers, perennials) are better started indoors to give them (and us!) a good head start on the season.

Whenever possible, direct sowing seed is preferred, as it usually gives the best results, because transplanting always causes some degree of stress and can delay maturity by a couple of weeks from plants adjusting to their new environment. We’ve got a detailed list of what to start where in this blog, Starter Plants or Direct Sow?

Simple Compost System

Q. How do I start my compost an easy and cheap way? I have seen many different ways to do it but I don’t know what exactly do I need to start it. Like do I need to start off with some soil and then add stuff to it? Thank you in advance!

A. Yes, absolutely. The earth has been composting since forever and so we want to just create conditions to help the natural process along.

  • Start with a 3’x3’x3′ space in contact with the ground, in part sun (if possible) to start the simplest kind of compost system.
  • You can collect leaves in the fall to get you started on this size pile. Add only plant-based material (egg shells and manure are exceptions) to prevent odors while keeping things simple and safe.
  • Here is the general idea–add 1 part “green”, nitrogen-rich, still living material like food scraps, manure or green grass clippings to 30 parts “brown”, carbon-rich material like brown/dried leaves, cardboard, spent potting soil, and dried grass clippings.
  • Water your pile so it has the consistency of a rung-out sponge and if you can, turn and mix the pile as often as twice a month to help speed the process.

By starting a pile on the soil, you do not need to add anything to get it going, as the organisms will naturally come. We talk more about starting a compost pile in our article, Composting 101.

If you don’t have the outdoor space, you may want to look into building an indoor worm bin, which can usually be done for about $30 or contacting your trash service to see if they have a composting program.

Do I Need Raised Beds?

Q.Currently my whole backyard is a big patio (that has a pretty thick layer of limestone beneath the pavers), and we’re looking to dig up a big section of it to start a garden and just wondering if I’ll need to spend the whole summer making the soil healthy again (presuming it’s a bit ~under the weather~) and then do my first planting next spring?

If yes, what is the best and most efficient way to “revive” soil? Also, what do you advise in terms of beds- raised, or right in the ground? Thanks for your advice/suggestions/help and time!

A. Good for you! Adding more garden space always makes us happy! If you have at least 18″ of soil above the limestone, building raised beds should not be necessary. Assuming you have that soil depth, step one would be to submit a soil test to a cooperative extension office or private soil-test company to see what your soil health is currently and the results will also come with recommendations on what to amend your soil with to be more ideal for growing.

Soil tests cost around $20-$30 and save a ton of time, money, and energy. In most cases you can amend your soil and get growing right away so there is no need to take a long pause, which in open soil can lead to a buildup of weed seeds that can drop in over the season.

After your first season, it is usually safe to assume the garden needs nitrogen and organic material added annually to replenish all the nutrients that were removed by harvesting flowers and vegetables, and even from weeding. Plants need much more than that though, thus the recommendation of a soil test.

We’ve got more about soil tests in our article Soil Tests 101 and some plant nutrition basics in the article, How do I Know Which Fertilizer to Use?. Congratulations on planning your new garden space!

Seed Starting Indoors

Q.Thanks for taking questions! We are having the hardest time starting vegetables like tomatoes, peppers, bok choy and kale from seed (or any food for that matter). We live in MA and started them inside, in a sunny window, in Ziploc® bags to create a greenhouse feel. Any help on best practices on starting seeds inside? Thank you so much!

A. Luckily, we’ve got some experience around here gardening from seed. I can give you some information on starting seeds indoors and some links to some of our articles to help.

First let’s talk about seed starting containers. Lots of things can work well. You can even upcycle yogurt containers or an egg carton; just make sure the container is clean, sterile, and has good drainage.

Next, starting seeds in seed-starting mix is ideal because it is sterile (unlike garden soil which can contain pests or disease) and it holds the ideal amount of water and air for seed sprouting. Soil temperature is another crucial variable; if you are outside the ideal range, seeds can take a really long time to germinate or may fail to germinate altogether, and sometimes even rot away in wet conditions.

Look for the ideal soil temperature range to be on the back of the seed packet in the sowing instructions and if it isn’t, you can assume the range falls within normal household temperatures.

Some seeds take longer than you may expect to germinate. You can know when to expect to see your seedlings (in ideal conditions) by looking for “days to emerge” on the plant tag section on the back of the seed packet.

A plastic bag, like a Ziploc®, doesn’t provide fresh air or drainage, and on a windowsill could be drafty making the soil cool.

Here is an article all about Seed Starting Indoors that goes into some more detail.

Garden Pests

Q. Pests! I haven’t been able to enjoy any of my cauliflower, radishes, peppers or even marigolds because the snails and worms get them first. I’ve tried beer traps, 1/2 orange rinds, “1st Saturday lime”, eggshells and coffee grounds. Only thing left is Neem oil?

A. Pests being pests–we hear you. There are a few simple solutions that I think will work for you. Assuming you are talking about cabbage worms or cabbage loopers here, those caterpillars that chew through the leaves of our beautiful broccoli, kale, and other brassicas.

The simplest, low-maintenance way to protect brassica crops from these caterpillars is to cover the sown area or the plants with row cover right after sowing or transplanting. This excludes the moths and butterflies that lay the eggs and you can uncover to harvest your beautiful greens and then batten down the hatches again to keep them protected.

Since brassicas do not need to be pollinated in order to produce a crop you can keep them covered indefinitely. Neem and Bt (Bacillus thuringiensis) are also organic options but will need to be reapplied regularly to keep the population down. You can also scout for and destroy eggs, but it can be difficult to find every egg since these pests don’t necessarily lay them in clusters.

Next up, let’s talk about those slugs and snails. You mentioned some good methods. Here are some others that can help. You can protect plants by surrounding them with diatomaceous earth (reapplying after rain) or copper tape. (Learn more about organically removing pests here: Pests: Organic Management)

Damping Off

Q. I’m trying to eliminate peat in my garden, however this year I created a seed starting mix using coir and perlite instead and I have had horrible issues with damping off. I cleaned all pots using hot water and soap and all new potting materials.

Almost all my seedlings except for the Cucurbits have died 🙁 only thing I can think of otherwise is some fluctuation in ambient temp? While I have them on a heating mat, the heated greenhouse they are in doesn’t have cooling. Any ideas?

A. Damping off can be devastating! The plant keels over at the soil line where the fungus attacks the stem. We’ve got a simple proven solution for you that is probably right in your pantry–cinnamon!

Cinnamon kills fungi like the one that causes damping off and can be safely used around your plants (avoid the leaves). If you are not sure if the problem is damping off, it could be the medium you created. Coir is quite acidic and usually requires an additive to buffer the acidity for growing.

It is really good to clean your containers like you mentioned, but also to sanitize them with whatever you feel comfortable with, which could be a bleach solution, vinegar solution, or perhaps hydrogen peroxide. Temperature is also very important.

Use a greenhouse thermometer to record minimum and maximum temperature so you can be sure the cold-sensitive plants aren’t getting too cold.

Container Gardening

Q. Any tips for urban gardening with limited space and only planters?

A. Container gardening is absolutely viable. Pretty much anything can be grown in a container, as long as the container is big enough and has drainage. Full sun (over 6 hours a day) opens up the possibilities of growing any vegetable or herb and a lot of flowers too.

Here are some examples of crops that can grow in smaller spaces: summer squash, beans, tomatoes (determinate types stay short), greens, lettuce, beans (pole beans produce longer but need support), cucumbers, compact winter squash, peppers, eggplant, and peas.

For flowers, the opportunities are nearly endless, but choosing varieties that are not too tall (under 4′) will help keep planters from toppling over. Pay attention to your potting medium and add nutrients if it does not contain any, or plan on feeding your plants with liquid fertilizer. And you are off…!