Category Archives: starting seeds indoors

When should you plant garden seeds?

Just the beginning…

A week ago I started my seeds indoors for this summer’s garden. Normally the “last frost date” in this area is around May 17, although some sources day as late as June 1—nearly three weeks later than Denver, which is only about 20 miles away! But our elevation is higher and we’re in a more open area than Denver proper, which has it’s own microcosm. I’m aiming for a May 3 or 4 plant date, two weeks earlier than advised, but my hoop frames with row covers will protect the garden from late-season snow and frost.

Wondering what your last frost date it? A great online source for that information is the Farmer’s Almanac web site. All you need to do is enter your town or zip code into the search box and the site will not only give you a last frost date, but also a list of vegetables, when to start your seeds and when to set the plants out—all based on your frost date. Each vegetable on the list is a link to more in-depth information on how to grow that specific veggie. What a great resource! They even have an amazing on-line garden planner that you can use for free for 30 days. 
Seed start planning!

Taking plant dates even a little farther, I put together an Excel chart listing only the vegetables I plan to grow. For plants that didn’t appear on the Farmer’s chart, I either used the recommendations on my seed packages, the charts that come in Park’s Seeds catalogs or looked for an on-line source such as Heirloom Seeds. Some seeds will be sown directly into the garden, on my plant date, so those went to the bottom of my chart. I then sorted the list by seed start date. I’m putting the Excel chart up here for download if you’re interested. You can then personalize the chart for your particular plants and planting schedule. If you don’t have Excel, here’s a PDF version that you can edit by hand. You’ll see a column labeled Actual. I decided to keep track on actual germination time, which can vary depending on temperature of the room in which you’re starting your seeds.

I have sunshine on
a cloudy day!

This year I moved my seed starting operation to a small upstairs bedroom with a south-facing window. It’s very easy to keep that room warm—much warmer than the rest of the house. I bought a second LED grow light to double my coverage, and added a humidifier for moisture and a little more heat, especially for those overcast or snowy days. I was very surprised to see that the first plants to germinate, chamomile and cabbage, came up within three days of planting. Their germination time is supposed to be roughly 7-14 days! In fact, everything I planted last week, with the exception of peppers (bell and Anaheim) and celery, are up and growing. I think I’ll photograph their progress every Sunday and update this post with the photos.

If you’re growing your garden from seed this year, you’d better get to work now! Here is a more detailed post on starting plants from seeds from March of last year.

Indoor gardening — Is it feasible for the average home owner?

What do urban farmers do in the winter, when they can’t get their hands on decent tasting tomatoes and herbs? When their green thumbs long for gardens during long, cold, snowy winters? When they get tired of paying a fortune for fresh organic produce that doesn’t taste any better than the rest of the produce in the store? This urban farmer brings the garden indoors.

Last year’s seedlings

For years I’ve successfully started my outdoor garden from seeds germinated indoors, weeks ahead of time. A couple of years ago I bought this amazing LED grow light that made my seedlings flourish like never before. The first winter I bought it I tried growing a number of veggies and herbs, not intending to keep them very long. I was just curious how they’d do.

Indoor garden

But a few weeks under the light gave me fully edible chard, collards, parsley, basil and other herbs. The tomato plants had a  little tomatoes on them and the green beans had miniature beans growing. I was impressed!

This fall I decided it would be a fun experiment to try to make it through the entire winter growing tomatoes and herbs indoors. I wish I’d started earlier, like maybe in September. But I didn’t get things planted until after Thanksgiving. I started with the typical little plastic seed packs and seed starter mix. One each of three different  types of tomatoes: Costoluto Genovese, Brandywine and Roma. Some basil, dill, parsley, oregano and sage. Rosemary from the store. I also started some white sage, which I never had luck germinating previously.

White Sage & Dill

Once the seeds sprouted, I moved them to the window in the guest bedroom. It’s south-facing so it gets a lot of our hot Colorado winter sun. It’s also the warmest and most temperature place in the house. I hung the grow light over the plants using a light stand with a boom arm. The light was just under 12″ from the plants. I plugged the light into a timer– one less thing to think about.

Within about 3 weeks the plants were outgrowing that space. I moved the guest room furniture to a different room to make more space. I bought this great stainless rack at target and placed it front of the window. Since the shelves are very adjustable, I gave the now overgrown tomatoes a shelf to themselves, with a short shelf above them for the herbs. The grow light sits on yet another shelf above that. I position the herbs in a way that the tomatoes below them can still get light from the LED and everyone is happy.

Lemon tree

In the beginning I was only running the grow light from 4 pm (sunset) until 10 pm.  But the plants weren’t looking as healthy as they should. They weren’t the deep green I wanted and some were getting a little spindly.  A happy plant will look strong and stocky. So I increased grow light time until midnight. That, plus the slightly longer daylight since we’re past the solstice has made a big improvement. I added a cool temp humidifier, although I’m not sure I need it. On sunny days I swear it gets close to 90 in there! I found a variegated lemon tree at the grocery store and that’s now producing new leaves. Let’s see if I can keep it alive.


I’ve been using the herbs for cooking almost every day. The basil especially impresses me since I think of them needing a lot of light in the garden, but they look perfectly normal indoors.


The tomatoes have little fruits on them and I’m curious if they’ll get large enough to ripen. And how long might that take? If they’re still around in late May, I will most likely introduce them to the outdoors. I’m also curious if they will taste better than store-bought tomatoes. If they don’t, I’ll ditch my goal of growing tomatoes indoors in the winter and just stick to herbs. After all, why buy those teeny $4.00 packets of herb snippets in the grocery store when it’s so easy to grow my own for the cost of one seed?

If the tomatoes are a success, I’ll keep better records next year on plant dates, grow time and even photograph them weekly to have a clearer idea of how they’re doing.

It’s now early February.  I’ll update this post at some point to let you know how things are getting along. Wish me luck!